Why? To deflect attention from all the stuff going haywire up here...growing disaffection of US population, resistance to his federalizing all Nat'l Guards, revelations about more GOP pedophiles and anger about Maxwell's special treatment, desire for the Epstein files, court rulings on tariffs...
and more. Like so many GOP politicians, the would-be peacemaker sees acts of war as generating "unity" in the population...like his air strike on Iran... and since the meeting with Putin didn't garner lots of praise AND a Nobel Peace Prize. Like all political idiots in the world, he thinks,
to the extent he can think, that short victorious wars are easy to cook up and wipe up afterwards. They're not, of course; more than one president, prime minister, king has fallen into that trap. War is expensive ($$$, lives, reputations), nasty, dangerous, destructive, and unpredictable.