Growing signs suggest that U.S. President Donald Trump could restart the war with Iran following the U.S. midterm elections on Tuesday.

While there have been renewed diplomatic efforts to reach a deal over the past week, the terms Iran has put on the table—including lifting all U.S. sanctions—would be difficult for the United States to accept. Meanwhile, Trump has offered mixed signals on what he plans to do, indicating that he hasn’t yet made a decision. Over the weekend, Trump said the war could be over soon, but he also said that the U.S. still had to “take care” of one or two nuclear sites and would have to give Iran “the hammer” at some point.

The war has cost U.S. taxpayers an estimated $47.1 billion so far and has left the United States military depleted on a number of levels—from drastically reducing key munitions stockpiles to the destruction of expensive equipment and aircraft.

The U.S. is estimated to have used up to 65 percent of its Patriot air-defense interceptors and 80 percent of its Terminal High Altitude Area Defense (THAAD) ballistic missile interceptors since the war began, for example. The U.S. stockpile of Tomahawk cruise missiles is estimated to have fallen from around 3,000 to 2,000 since the fighting started, and the war has reportedly left its stocks of missiles for the Army Tactical Missile Systems, or ATACMS, and precision strike missiles almost exhausted. Around a quarter of the U.S. military’s MQ-9 Reaper drones have also reportedly been lost during the war. Rebuilding these stockpiles will take years.

All of this raises questions about U.S. military readiness and capabilities if Trump chooses to return to war post-election.

The United States still has significant military capabilities in the Middle East, including over 50,000 troops and two aircraft carrier strike groups. Another aircraft carrier strike group is en route and should arrive near the end of this month.

Longer-range and more advanced capabilities like Tomahawk missiles are “significantly depleted,” and Patriot and THAAD batteries are “limited,” but there are “other ways for the president to be able to successfully execute the missions he’s looking at,” Jonathan Panikoff, the senior director of the Scowcroft Middle East Security Initiative at the Atlantic Council, told Foreign Policy.

“In the short term, the U.S. is likely quite ready to carry out the planned operations,” said Stacie Pettyjohn, a senior fellow and director of the defense program at the Center for a New American Security. An additional Patriot unit was sent from Texas to Israel, for instance, and the Pentagon has likely dispersed aircraft and personnel from bases that are very close to Iran and less well defended, such as in Bahrain and Al Udeid Air Base in Qatar, Pettyjohn said.

But that’s just the short term. The picture could change drastically over a longer time horizon.

“The long-term readiness concerns are quite profound,” Pettyjohn said. These constraints include “munitions stockpiles”—for example, long-range standoff attack missiles and defensive interceptors—“deferred ship maintenance, and disrupted readiness cycles, which affect what forces will be available for future contingencies.”

The U.S. has reportedly told Gulf allies to brace for a short but intense campaign targeting Iranian infrastructure and nuclear sites, with the goal of strengthening Washington’s negotiation position. But Trump has consistently struggled to dictate the direction of the war, and Iran has proved to be a resilient adversary. The U.S. and Israel conducted thousands of strikes on Iran, but Tehran has not budged in its demands. Iran has also exhibited an ability to quickly adapt its tactics and has proved that even with a diminished military, it can disrupt the flow of traffic through the Strait of Hormuz.

“If Iran has prepared for a more protracted campaign of attacks against U.S. forces in the region and civilian infrastructure, that could quickly drain near-term U.S. readiness. So overall, restarting the war would be a huge gamble,” Pettyjohn added.

Iranian Supreme Leader Ayatollah Mojtaba Khamenei during a recent meeting with commanders reportedly said that Iran’s response would be “immediate, effective” and “without any geographical limitations.” Iran would likely move to strike U.S. bases in the region and energy facilities in Arab countries in response to the war restarting, but it has also signaled that a wider menu of civilian infrastructure could be targeted.

“It is impossible to defend everywhere,” Pettyjohn said. “The U.S. can in the short term surge fighter aircraft to help interdict incoming drones and to potentially suppress Iranian launchers, although the latter must fly over Iran and is at risk of being shot down. But that is a difficult posture to sustain indefinitely as aircraft are likely operating from more distant bases, flying long sorties, and require lots of tanker support.”

Resupplying forces that are under attack with additional weapons would be difficult as well, Pettyjohn said.

The decisions that Trump makes with regard to Iran will also have an impact on U.S. military capabilities in other theaters moving forward. The “more capabilities” that are used against Iran, Panikoff said, “the less that are available for other potential conflicts in the future.”