A protracted Iran war multiplies risks for Trump

These numbers are quite low compared to historical levels of US public opinion at the start of military campaigns—the Iraq and Afghanistan wars in the 2000s, as well as the fight against the Islamic State in the 2010s—when the wars had majority support among the American public. Public support for these wars declined over time as the costs in American lives and US taxpayer dollars rose. 

US presidents typically seek to build national consensus to unify the country during war, but that's not how Trump operates. He used his State of the Union address last month to divide the country on a wide range of domestic and foreign policy issues, and he only briefly mentioned Iran towards the end of a long speech.  In addition, when America enters a conflict, it often produces a "rally around the flag" approach in the early days, with Americans looking to support US troops in harm's way. 

But that wasn't the case in the opening days of this war on Iran, which may be one of the reasons why President Trump and his team might be signalling that they would like to wrap up this war sooner rather than later. With midterm elections less than nine months away, the last thing he wants to see is a further erosion of public support, which was already at its lowest point before this unpopular war began, with 6 in 10 Americans disapproving of the job Trump is doing overall. 

A defiant Iran

For their part, Iran's Islamic Revolutionary Guard Corps says it will be the one to "determine the end of the war", reacting to Trump's comment on Monday.

"The equations and future status of the region are now in the hands of our armed forces; American forces will not end the war," the statement added.

One potential political liability for Trump with this war is the risk that the spike in gas prices from the Iran war could further weaken US public perceptions about how he has handled the economy and inflation, which remain the top concern among US voters.  A Reuters/Ipsos poll conducted this past week found that 67% of Americans expect gas prices to rise after the Iran strikes. A second vulnerability in this war comes with the risk that more US troops could die in combat.

In this domestic political context, Trump's decision to go to war against Iran alongside Israel, without much of an attempt to build public consensus, could prove to be reckless—especially given the fact that the decision was taken without consulting or support from regional partners, like Saudi Arabia, Qatar, the United Arab Emirates, Egypt and Jordan.

In the end, US public support for the Iran war will be closely linked to how things fare on the battlefield. It may be that the tactical successes of eliminating the Iranian regime's top leaders on day one could serve as the high-water mark of success unless the Trump administration offers a clearer end goal to the US public. The longer this war drags on, the riskier it becomes for Trump.