The only consistent Republican candidate, to the point of rigid adherence to conservative orthodoxy, is Sen. Ted Cruz (Texas). But his hard-line approach has not taken him to the top of the polls.

Louisiana Gov. Bobby Jindal has flipped on Common Core, too. Last year, the Republican head of the state Board of Elementary and Secondary Education said the governor’s move away from Common Core was “about presidential politics.”

The same point applies to Walker. He had Common Core included in the state budget in 2011. But as his presidential ambitions grew in 2014, Walker announced he wanted the state legislature to repeal Common Core and “replace it with standards set by the people in Wisconsin.”

Meanwhile, Sen. Marco Rubio (Fla.) is flip-flopping over immigration reform. He was one of the authors of a 2013 Senate bill, and its pathway to citizenship for millions of people. Now that he is running for president, the son of Cuban immigrants is putting border security above reform. This flip-flop makes it tricky for him to point out that he put a massive spending increase for border security in the Senate bill.