How has the president avoided a rebellion within his own party? No doubt congressional Republicans fear Trump because of his unshakable grip on the party’s base. That’s long been the case. But there’s another reason they’ve shielded him from impeachment: He’s wooed Republicans who can protect his interests, cultivating relationships with them in ways that are not always visible or understood. So much of Trump’s presidency seems like a jagged break from history. Yet when it comes to reaching out to his own party, his method isn’t all that different from that of his predecessors—and it’s helping him survive the biggest domestic crisis of his presidency.

An impeachment wildcard is the military strike Trump ordered against the Iranian general, Qassem Soleimani. Americans tend to rally behind a president facing looming national-security crises, and lawmakers take cues from voters. That could help strengthen Trump’s impeachment advantage within his party, and even Democrats from conservative states might be more sympathetic to the president in a Senate trial if Trump is overseeing an armed conflict with Iran.