When the conflict in Iran first began, about half of the self-identifying MAGA voters thought it was worth its economic costs, per POLITICO polling. Now, only a little more than a third do. That's a 13-point decline.

By The Numbers:
Just two months ago, 50% of self-identifying MAGA voters said “the US should continue its involvement in Iran, even if it increases costs in America.” Twenty-nine percent said “the US should only continue its involvement in Iran if it does not increase costs in America,” and only 12% said “the US should not continue its involvement in Iran, regardless of costs here in America.”
Today only 37% of self-identifying MAGA voters said the US should continue the involvement in Iran despite the cost, a drop of 13 points from May. Thirty-seven percent said “the US should only continue its involvement in Iran if it does not increase costs in America,” and only 19% said “the US should not continue its involvement in Iran, regardless of costs here in America.”
The Bottom Line: As many noted at the time, the concessions made in the June 17 Memorandum of Understanding risked disappointing Trump's base by making Team Trump appear weak in the negotiations. After the MOU collapsed in July, Americans are likely more confused and frustrated than ever. Polling should never dictate how a president approaches action in war. But clearly communicating the administration's goals and strategy will help sustain public support.