Is there really? There’s some grumbling online, and the recent debt ceiling fight did involve a cap on spending. But they still increased spending, and it’s entirely possible and probable that cap is going to get uncapped in a supplemental, as Republican and Democrats in the Senate are still quite into spending on this.
https://www.nbcnews.com/politics/congress/mcconnell-says-mil...
The US populace may get grumbly about spending on Ukraine, although realistically most people are just bored and have tuned out that news. But I think there’s about a 0% chance we won’t still increase military spending, especially given even more posturing and escalation about Taiwan.