Thatcher, like Reagan, was open to new ideas. They governed based on core convictions but were tolerant of 80 percent solutions — of trade-offs, negotiation, even the occasional heresy. When William F. Buckley Jr. parted company with the policy objectives of his two friends, they did not disavow him. They did not exclude him from gatherings. They did not question his conservative credentials. They simply disagreed.

What a contrast to the so-called conservative GOP that followed them. A few years later, when Buckley questioned the wisdom of the Iraq war and George W. Bush’s 2008 surge, he was all but drummed out of the conservative movement. “If you had a European prime minister who experienced what we’ve experienced, it would be expected that he would retire or resign,” Buckley once said of Bush. For such apostasies, Bush aides threatened to ban Buckley from the radio airwaves. (I know because I was there.)

Today, Republicans who think and scrutinize and muse out loud are punished. Former Florida Gov. Jeb Bush and Sen. Marco Rubio (R-Fla.) are pilloried as apostates for championing immigration reform, as they chastise conservatives with a different view. Yet, would it surprise Republicans to know that Reagan supported tough border enforcement as well as amnesty?

Boehner made headlines in December for purging from plum House committees those who didn’t toe his line. GOProud, a Republican gay rights organization, reaped endless, and needless, publicity because some conservatives wouldn’t let it sponsor this year’s Conservative Political Action Conference. Such maneuvers deviate from the “big tent” philosophy Reagan and Thatcher championed.

To this day, Sen. Rand Paul (Ky.) draws jeers from the Republican establishment for an approach to foreign policy whose caution and restraint is closer to Reagan’s and Thatcher’s than today’s GOP ever was. “Don’t fall into the trap of imagining that the West can remake societies,” Thatcher wrote after the attacks of Sept. 11, 2001. “Anyone who really believes that a ‘new order’ of any kind is going to replace the disorderly conduct of human affairs, particularly the affairs of nations, is likely to be severely disappointed.”

Had Thatcher invoked such sentiments as a Republican senator during Bush’s presidency, she would have lost her primary.

New Jersey’s Chris Christie, one of the party’s best blue-state governors, still suffers ostracism from national Republicans for daring to praise and work with Obama. Yet Reagan periodically praised Franklin D. Roosevelt and John F. Kennedy; and in her memoir, Thatcher even lauded Jimmy Carter.

Thatcher and Reagan showed that core convictions and compromise were not at odds — indeed, that the two impulses reinforce each other. Somehow, today’s GOP leadership has pulled off the impossible: discomfort with both.