Donald Trump's war with Iran has already cost American taxpayers an estimated $45.1 billion.

The bill is still growing.

But voters heading to the polls in November may not know how Congress intends to pay for it until after the election is over.

According to figures the Pentagon provided to Congress, the military had accumulated approximately $43.6 billion in Iran-war-related costs through September 3. Another $1.5 billion was allocated for additional fuel, bringing the total to roughly $45.1 billion.

And even that isn't necessarily the complete bill.

The Pentagon figure does not include some expenses associated with repairing damaged American military facilities and other indirect costs of the conflict.

The nonpartisan Congressional Budget Office separately estimated that military operations against Iran had cost approximately $38 billion through August 1.

The difference largely reflects different cutoff dates and accounting methods.

But both estimates point in the same direction:

America is spending billions of dollars every month on a war that has now lasted far longer than originally suggested.

And Washington still hasn't settled how to pay for it.

An $87.6 Billion Request

In June, the Trump administration asked Congress for an additional $87.6 billion in emergency spending.

Of that amount, approximately $67 billion was requested for the Pentagon.

The package included billions for munitions, military operations and classified programs, although independent analysis has found that not all of the money can accurately be described as direct Iran-war spending.

The Center for Strategic and International Studies estimated that roughly one-third of the overall $87.6 billion supplemental request appeared directly driven by the Iran conflict.

Other portions would replenish weapons stockpiles or fund broader Pentagon priorities.

That distinction matters.

The administration isn't asking Congress simply to write an $87.6 billion check labeled “Iran War.”

But the war has unquestionably created tens of billions of dollars in costs, and those costs continue accumulating.

Congress Keeps Spending — Without Settling the Question

Congress has spent months fighting over how to deal with the war.

The House approved a $95 billion budget resolution that could provide roughly $73 billion for the conflict and other priorities.

But that legislation has not become law.

Congress subsequently passed temporary legislation keeping the federal government operating through December 11.

What wasn't included was a final resolution of the administration's emergency war-funding request.

That creates an extraordinary political situation.

Americans will vote on November 3.

The temporary government funding measure doesn't expire until December 11.

Congress can therefore return after the election and confront the enormous Iran-war funding question during the lame-duck session.

Voters will have already cast their ballots.

The War Itself Has Never Received Normal Congressional Authorization

The funding fight comes alongside another unresolved constitutional dispute.

Congress has repeatedly considered resolutions attempting to restrict Trump's ability to continue military operations against Iran without explicit congressional authorization.

On September 24, the Senate rejected another war-powers resolution by the narrowest possible margin: 50-49.

Four Republican senators — Susan Collins, Lisa Murkowski, Rand Paul and Thom Tillis — joined most Democrats in supporting the measure.

Democratic Sen. John Fetterman voted against it.

The House has separately passed measures seeking to restrict or end American participation in the conflict.

The Trump administration has maintained that it possesses sufficient authority to conduct the military operations.

Critics in both parties argue that a conflict lasting many months and costing tens of billions of dollars requires explicit authorization from Congress.

That argument is no longer theoretical.

American troops are fighting.

American servicemembers have been killed and wounded.

American weapons and ammunition are being consumed.

American military facilities have been damaged.

And American taxpayers are paying the bill.

And the Meter Is Still Running

The Congressional Budget Office estimates that another month of fighting could cost approximately $2 billion if combat remains at levels seen earlier in the war.

If fighting intensifies, CBO estimates monthly costs could reach approximately $3 billion.

And those figures carry considerable uncertainty.

That means the $45.1 billion Pentagon estimate isn't the final price of Trump's Iran war.

It is essentially the running total.

The longer the conflict continues, the larger that number becomes.

The financial consequences also extend beyond Pentagon spending.

The conflict has disrupted global energy markets, contributing to higher fuel prices that affect American motorists, airlines, farmers, trucking companies and businesses throughout the economy.

Those costs don't appear on a Pentagon balance sheet.

Consumers encounter them at gas pumps, grocery stores and in transportation costs.

Americans Will Vote Before Washington Settles the Bill

That may be the strangest part of the entire situation.

By Election Day, Americans will have watched the Iran war continue for months.

They will know that tens of billions of dollars have already been spent.

They will know American troops remain deployed.

They will know that Congress has repeatedly fought over whether the president should be permitted to continue the conflict without explicit authorization.

What they may not know is exactly how much additional money Congress will ultimately approve to finance it.

That decision can wait until after the ballots are counted.

There are legitimate disagreements in Congress over both the war and how it should be funded. Republicans and Democrats have backed competing approaches, and members of both parties have crossed party lines on war-powers votes.

But the accounting problem doesn't disappear because Congress postpones the decision.

The Pentagon says approximately $45.1 billion has already been spent or allocated.

The administration has requested tens of billions more.

The war continues.

And five weeks after Americans choose the next Congress, the government's temporary funding measure expires.

The fighting isn't waiting for Washington to make up its mind.

Neither is the bill.