While US President Donald Trump is deploying more warships and troops to the Middle East, about 59 per cent of Americans say military action in Iran has been excessive, and many are worried about affording gasoline, according to a new poll.

The poll findings coincide with the Pentagon’s statement on Wednesday about reaching an agreement with BAE, Lockheed and Honeywell to boost production of defence systems and munitions as part of its shift to "wartime footing."

The survey from The Associated Press-NORC Centre for Public Affairs Research indicates that while Trump's approval rating is holding steady, the conflict could be turning into a major political liability for his Republican administration.

The AP-NORC poll of 1,150 adults was conducted March 19-23 using a sample drawn from NORC's probability-based AmeriSpeak Panel, which is designed to be representative of the US population. The margin of sampling error for adults overall is plus or minus 4 percentage points.
Forty five per cent are "extremely" or "very" concerned about being able to afford gas in the next few months, up from 30 per cent in an AP-NORC poll conducted shortly after Trump won re-election with promises that he would improve the economy and lower the cost of living.

There is significant support for at least one of the President's objectives, which is preventing Iran from obtaining a nuclear weapon.

About two-thirds of Americans say that should be an "extremely" or "very" important foreign policy goal for the US. And they are just as likely to say it's important to keep US oil and gas prices from rising, a juxtaposition that could be difficult for the White House to manage.

About 4 in 10 US adults continue to approve of Trump's performance as President, which is unchanged from last month. His approval on foreign policy, while slightly lower than his overall approval, also largely held steady.

Trump has left unclear his next steps on Iran. Despite escalating threats, he's also suggested diplomatic talks could resolve the conflict.

Americans remain apprehensive about Trump's ability to make the right decisions on the use of military force outside the US, and they oppose more aggressive steps, such as deploying ground forces, according to the poll.

Under the terms of Wednesday's Pentagon deal with defence companies, Honeywell Aerospace will "surge production of critical components for America's munitions stockpile," as part of a $500 million multi-year investment, the Pentagon said.

BAE Systems and Lockheed Martin will also quadruple production of seekers for the Terminal High Altitude Area Defense (THAAD) interceptor, while a new framework agreement with Lockheed will accelerate production of its Precision Strike Missile, the Pentagon added.

Republicans and Democrats prioritize keeping gas prices low

Keeping the price at the pump down is the rare goal that unites Americans in both major political parties.

About three-quarters of Republicans and about two-thirds of Democrats say it's highly important to prevent US oil and gas prices from going up.

However, concern about the current situation isn't evenly felt. Only about 3 in 10 Republicans said they're "extremely" or "very" worried about affording gas in the next few months, as opposed to about 6 in 10 Democrats.

Trump's focus on Iran's nuclear program also appears more compelling to Republicans than to Democrats. About two-thirds of Americans say the US should prioritize keeping Iran from obtaining a nuclear weapon, but about 8 in 10 Republicans say this is at least "very" important, compared with about half of Democrats.

The war has exacerbated political debates over the role that Israel should play in US foreign policy, especially since Israeli Prime Minister Benjamin Netanyahu was a leading voice for attacking Iran. Only about 4 in 10 US adults say preventing Iran from threatening Israel should be a high priority.

Toppling Iran's leaders is viewed as slightly less important. Only about 3 in 10 say it's at least "very" important for the US to replace Iran's government with one that's friendlier to US interests.

Most Americans say US action has gone too far in Iran

As Trump provides mixed messages on whether the Iran war will end soon, about 9 in 10 Democrats and about 6 in 10 independents say the Iran attacks have "gone too far."

Republicans are more divided. About half of Republicans say the US military action has been "about right," but relatively few want to see it go further. Only about 2 in 10 Republicans say the US military action has not gone far enough, while about one-quarter say it's gone too far.

Recent AP-NORC polling has found that about 6 in 10 Americans say Trump has "gone too far" on a range of issues, including his approach to tariffs and presidential power. That number, which is broadly reflective of his overall approval, signals that while Trump's actions in Iran are unpopular, it's still comparable to other controversial moves he's taken as president.

Further entrenching the US in the war could change that, depending on what happens next. About 6 in 10 Americans "somewhat" or "strongly" oppose deploying US troops on the ground to fight Iran, including about 8 in 10 Democrats and roughly half of Republicans.

Just under half of Americans oppose airstrikes targeting Iranian leaders and airstrikes against military targets in Iran, while about 3 in 10 are in favour and about 3 in 10 don't have an opinion.

Many Americans distrust Trump on use of military force abroad

About half of US adults have "only a little" trust or "none at all" in Trump when it comes to making the right decisions about the use of military force outside the US, in line with an AP-NORC poll from February.

About 34 per cent of US adults approve of the way Trump is handling foreign policy, similar to 36 per cent in February. That measure has been consistent in recent months despite a cascade of actions, including confrontations over Greenland and an attack on Venezuela, that have generated controversy at home and abroad.

It's also very similar to Trump's approval on Iran in the new poll, which found that 35 per cent of Americans have a positive view of his handling of that issue.