Whatever Trump's overall approval rating is, his power derives from the fact that Republicans control Congress and that the GOP base is almost completely — and passionately — behind him. GOP members of Congress who have clearly been taken aback by Trump's behavior and are wary of his flirtation with Russian President Vladimir Putin have been muted by the simple fact that criticizing Trump comes with massive personal and political costs. It's why Trump's biggest critics are almost uniformly those who are retiring or don't have to face voters again.
The moment Justice Anthony M. Kennedy retired was arguably the moment that the GOP's brand bargain with Trump truly paid off. Suddenly, a solid 5-to-4 conservative majority on the court became likely. Suddenly, all those blind eyes that were turned and all those halfhearted statements about Trump's actions were easier to justify. If you're a conservative, it's easy to convince yourself that Trump's presidency will wind up being a net positive, barring some huge disaster. And it's probably possible to dismiss all of these events in Europe as an unimportant sideshow — the ramblings of a man with basically no diplomatic pedigree.
It was easy to see the strategy behind Trump's NATO comments; Trump, after all, was trying to get other countries to chip in more to the common defense. But the comments in Britain are much more difficult to place in that context. Maybe Trump is trying to help his ally Boris Johnson in a bid to replace May. Maybe he's just doubling down on his nationalist, anti-immigrant policies.
Or, as more and more are suggesting, maybe he's seriously trying to undo the United States' most important and long-standing alliances with Western countries. Perhaps this is the culmination of Trump's gradual move toward a more isolationist or even pro-Russian stance. It's becoming harder and harder to dismiss that possibility.
But thus far we've basically heard crickets from Republicans. And critics of this approach probably shouldn't hold their breath, given what's happened domestically in recent weeks.