Dan McCarthy points out the political danger Trump has created for himself with the Syria attack:
Trump does not have the same margin of safety—or any margin. He is the least popular of any president in modern times at this point in his administration. But he endured plenty of bad polls in the primaries and general election last year as long as his core activists and supporters stood by him, and those same voters have been steadfast during these troubled first 11 weeks. Trump would be well-served if he could expand his base of support. But demolishing his existing base and replacing it with one that appeals to Bill Kristol or John McCain does not seem like a smart political move.
It remains to be seen how many Trump supporters choose to give up on him now, and some may end up coming back to him later, but the fact that he is in danger of losing any of his core supporters this early in his presidency bodes ill for the rest of his term. Activists and ideological voters often end up being disappointed with the president they’ve supported because of compromises or perceived betrayals, but that disappointment normally takes years before it takes hold. Trump is driving away some of his supporters within the first three months.
The opportunistic support he is getting from hawks in both parties isn’t likely to last and won’t help him on other issues, since many of them are otherwise opposed to Trump’s proposals or want to see him humiliated politically. The only way he can plausibly keep the hawks’ support is by digging himself and the country into even deeper holes in our ongoing foreign wars, but if he does that he will end up polling at second-term Bush levels very quickly. There was already a good chance that Trump would be “Carterized” on account of the divisions within the GOP and the administration’s own ineptitude, and he is making that outcome more likely by alienating at least some of the people that have stuck with him until now. Like almost all of the other wounds his administration has suffered, this wound was self-inflicted, and in this case Trump hurt himself by doing something that he could have easily avoided doing.