The armada gathers: America prepares the machinery for another attack on Iran

War usually announces itself before the first strike, not through speeches or declarations but through movement. Ships leave harbour, Marines embark, missile batteries are shifted towards the places most likely to be attacked in return, and supply vessels begin running longer routes across the ocean. Gradually, what may at first look like a series of unrelated deployments begins to resemble the assembly of a fighting force.

That is now happening around Iran.

The United States is building a naval concentration which, for a period after the November 3 midterm elections, could place three nuclear powered aircraft carriers, two amphibious assault groups, more than a dozen missile armed destroyers, Marines, stealth aircraft, electronic warfare squadrons and a floating expeditionary base around the Iranian theatre.

About 9,000 additional American personnel are being sent towards the region. If the arriving forces overlap with those already there, the American naval presence could rise above 20,000 sailors and Marines. The Pentagon describes the deployments as giving the president additional options.

President Donald Trump has also supplied the political timetable. He has said that heavier attacks on Iran after the midterm elections are possible and has suggested that he expects the war to be brought to an end shortly after the vote, if not before it.

The military movements do not prove that an attack order has been signed, but the political timetable and the military timetable are beginning to converge.

Professor Robert A. Pape has spent much of his academic career studying exactly this problem: how military power is assembled, concentrated and used to coerce an adversary. He is Professor of Political Science at the University of Chicago and founding director of the Chicago Project on Security and Threats. Before joining Chicago he taught air power strategy at the US Air Force’s School of Advanced Airpower Studies. His books include Bombing to Win: Air Power and Coercion in War and Dying to Win: The Strategic Logic of Suicide Terrorism.

His assessment is that the movement of so much American combat power should itself be regarded as a warning. The president can still decide not to use it. Ships can be turned around, one carrier can relieve another and diplomacy can intervene. But moving forces on this scale imposes costs in readiness, maintenance, ammunition, crew endurance and the availability of American warships elsewhere.

The first machine

On September 27, a Nimitz class nuclear powered aircraft carrier left San Diego and headed into the Pacific. There was little of the theatre that sometimes accompanies a major deployment. Sailors were not seen lining the rails and there was no grand ceremony as the carrier passed Point Loma. It simply went to sea and began the long journey west.

It is expected eventually to relieve another American carrier already operating in the Arabian Sea. That is a perfectly reasonable explanation for the deployment, but it does not remove the significance of what happens before the relief is completed. For one carrier to replace another, both must be available in the same broad theatre for some period of time, and a third American carrier is already operating there as well.

The result could be a window in which three American nuclear powered supercarriers are available around Iran at the same time. That would amount to considerably more than three large ships. Each carrier is a mobile airfield, command centre and ammunition magazine, surrounded by fighters, electronic warfare aircraft, airborne radar, helicopters, destroyers and missile defences.

A modern carrier strike group is better understood as a distributed weapons system than as a collection of individual ships. The carrier supplies the aircraft, while the cruiser and destroyers provide radar, missile defence and additional offensive firepower. Hawkeyes extend the group’s view far beyond the horizon, Growlers attack radar and communications, F-35Cs can penetrate defended airspace and share targeting information, and Super Hornets provide much of the conventional strike capacity.

Attack submarines may also be operating beneath the force, although the Navy does not publish their positions.

Two carriers are already waiting

Another American carrier is already operating in the Arabian Sea with its embarked air wing and a guided missile destroyer. A third carrier and its air wing are operating in the same broad theatre.

The significance of the carrier lies not only in the number of aircraft it carries but in the fact that it is mobile. It can move hundreds of miles in a day and carries with it workshops, ammunition magazines, radar, command systems and aviation support.

The second carrier already in the region brings another air wing and another missile armed screen.

Three American carriers would not simply multiply the number of flight decks. They would allow one group to launch aircraft while another recovered or replenished, complicate Iranian targeting, distribute radar and missile defence across a wider area and reduce dependence on land bases in the Gulf that have already been attacked.

For a limited period, it would represent an extraordinary concentration of American naval aviation.

The Marines behind them

The second movement towards the region is slower and serves a different purpose. On September 28, another American amphibious formation left San Diego carrying the 13th Marine Expeditionary Unit. A second amphibious group is already operating in the Arabian Sea.

This is not an invasion force, and two Marine Expeditionary Units would not be sufficient to occupy Iran. There is no public evidence that Washington is assembling the land forces necessary for such an operation.

What the Marines provide instead is flexibility. They can board ships, raid coastal positions, recover personnel, support special operations and put small forces ashore. The F-35Bs embarked on the amphibious assault ships also provide another source of tactical air power without requiring the flight deck of a supercarrier.

The missile screen

A further layer of the force consists of warships that do not fit neatly inside the three carrier groups. The open source fleet picture shows American destroyers spread across the Arabian Sea, Indian Ocean and Red Sea. Some are protecting carriers, while others are performing independent air defence, blockade, escort or missile roles and could be reassigned if circumstances change.

The scale becomes clearer when those ships are considered together. Each Arleigh Burke carries dozens of vertical launch cells, which can hold different combinations of air defence missiles, anti submarine weapons and Tomahawk land attack cruise missiles. They are defensive ships, but they are also strike platforms, which is why their concentration around the theatre matters.

Iran attacked the eyes

One of the first vulnerabilities Iran exploited was not the carrier force itself but the radar network behind it.

At least ten American or allied radar sites were struck during the opening weeks of the war, according to analysis of satellite imagery and verified material. The targets included infrastructure associated with missile warning and missile defence across Bahrain, Qatar, Saudi Arabia, Kuwait, Jordan and the United Arab Emirates.

The network was not destroyed, and that distinction is important. American sensors overlap, ships can contribute radar tracks and aircraft carry additional systems, so the loss of one installation does not blind an entire region.

But redundancy is not immunity. Every damaged radar reduces part of the available picture, while damage to communications can slow the movement of information through the network. In a missile war, even modest reductions in warning time can matter.

Iran had found a way to attack the eyes of the system rather than the weapons themselves.

Then it attacked its workshop

The more consequential blow may have been Bahrain.

For decades Naval Support Activity Bahrain was the physical centre of American sea power in the Gulf. NAVCENT and the Fifth Fleet operated from there, while warehouses, communications, support personnel and logistics sat close behind the ships they served.

Iranian missiles and drones penetrated the defences and damaged the command headquarters, satellite communications terminals, warehouses and numerous other buildings. Preliminary repair costs have been estimated at hundreds of millions of dollars.

The Chief of Naval Operations, Admiral Daryl Caudle, subsequently told sailors that the Navy was not returning to the base “anytime soon”. That removed something an aircraft carrier cannot carry with it: proximity.

The long artery

The American striking arm remains close to Iran, but the network sustaining it has been pushed backwards into the Indian Ocean.

Diego Garcia now plays a much larger role in sustaining operations, while material also moves through a wider system reaching towards Singapore, Japan, the Philippines and the United States. Navy leaders have described a continuous “combat logistics force treadmill” keeping ships at sea while the old Bahrain system remains badly impaired.

The mechanics are ordinary but relentless. Carriers and destroyers consume aviation fuel, ship fuel, missiles, aircraft parts, food, electronic components, hydraulic systems and countless other items which have to be replaced continuously. A nuclear carrier may not require conventional fuel to propel itself, but the aircraft above it burn fuel at an enormous rate and the ship cannot manufacture the parts, weapons and supplies required to keep those aircraft flying.

All of that has to cross the sea.

This is the part of naval warfare that rarely appears in dramatic photographs, but it is the part on which everything else depends. A carrier comes alongside a replenishment ship while both vessels continue moving, fuel hoses are suspended between them and ammunition, spare parts and food are transferred until the combat vessel can return to its station.

The supply ship then begins the long journey back through the Indian Ocean while another takes its place. The fleet survives only because that circulation never stops.

The strange arithmetic of power

This produces the central contradiction in the American force now gathering around Iran. At the front, it is immensely powerful. Three nuclear carriers could make scores of combat aircraft available at any one time, while two amphibious groups add Marines and additional F-35Bs. A screen of Aegis destroyers provides radar, missile defence and offensive firepower, and the fleet can manoeuvre across hundreds of miles of sea.

Behind it, however, the supporting infrastructure is more fragile than it was at the beginning of the war. Bahrain has been badly damaged, radar installations have been struck, ships have spent unusually long periods at sea, missile stocks have been consumed and the logistics chain has been stretched much farther into the Indian Ocean.

Pape has described the resulting choice with the old military expression that America may be preparing to “shoot our bolt”. He is not claiming to have seen an American operational plan. His point is about the logic of concentration: a force of this size has a peak and cannot remain at that peak indefinitely.

Ships eventually need dockyards, aircraft require maintenance, missile cells have to be reloaded and crews have to rotate home. Nor do America’s commitments elsewhere disappear because the war with Iran has intensified. The period in which the concentration is at its greatest may therefore also be the period in which Washington has the strongest military incentive to exploit it.

Preparing for the return fire

There is another movement taking place which is much quieter than the arrival of the carriers.

The United States has sent additional Patriot missile batteries to protect important energy facilities in Saudi Arabia and Qatar. Their purpose is defensive, but their timing is significant because Washington is strengthening protection around infrastructure Iran could attack if major American operations resume.

Iran, meanwhile, has also prepared for the possibility of a more severe response if it is attacked again. The forces required to conduct a larger offensive are therefore moving towards the theatre while the defences required to withstand retaliation are being strengthened at the same time.

The machinery before war

None of this establishes that Donald Trump has signed an attack order. The incoming carrier can ultimately relieve the carrier already in theatre, just as the incoming amphibious group can eventually relieve the one already operating there. Military concentrations can deter as well as attack.

But temporary overlap is precisely what creates a surge. For several weeks the United States could have three carrier strike groups, two amphibious ready groups, at least 30 publicly identified US Navy surface ships in the wider operating picture, additional Military Sealift Command supply ships and more than 20,000 sailors and Marines available across the region. The open source picture does not include every submarine, aircraft, tanker, special operations unit or support vessel, so the real force would be larger still.

Pape’s judgment is that the United States has little precedent for moving a force of this scale into position and then simply leaving it unused. That is an assessment rather than proof of a presidential decision, but it gives the deployment its significance when set beside Trump’s public suggestion that heavier military action could follow the midterm elections.

Preparations for war have a physical character that is difficult to disguise. Ships change course, aircraft move, missile defences appear around vulnerable infrastructure and supply routes are reorganised to support forces that may soon be used. Far out in the Indian Ocean, replenishment ships are already feeding the fleet through a logistics network that now stretches thousands of miles behind it.

The American striking arm is gathering close to Iran, while the artery that keeps it alive now stretches deep into the Indian Ocean. If another major American offensive follows the midterm elections, this is what the machinery before it looks like.