Many of the 2020 Democratic presidential candidates and would-be contenders have taken thoughtful and admirable positions on various issues over the years, eschewing blind partisanship and ideological dogmatism. Now they’re paying for it.

Sen. Cory Booker of New Jersey was for a long time an advocate of school choice as a means of liberating kids from failing schools, especially when he was mayor of Newark. In the Democratic presidential primaries, though, Booker’s support for charter schools will be a liability.

Even worse for him, he sometimes worked with Betsy DeVos, who as education secretary has become a hate figure for a lot of progressives. It may not be enough that Booker voted against her confirmation when President Donald Trump nominated her.

Former Rep. Beto O’Rourke of Texas has also gotten criticized for crossing the partisan aisle. The Guardian slammed him for voting for an immigration bill even though “Democrats adamantly objected” to it.

The legislation let the Customs and Border Patrol address a shortage of manpower by waiving the requirement of a polygraph test for former members of the military and law enforcement. That was a reasonable enough position that 51 Democrats, about a quarter of all House Democrats at the time, voted along with all Republicans for the bill.

O’Rourke has also come under fire for refusing to endorse a Democratic candidate over his friend, moderate Republican Rep. Will Hurd of Texas. He did say that the Democrat would be a good member of Congress if elected.

Sen. Kirsten Gillibrand of New York helped usher her former colleague Al Franken out of office after several women accused him of groping them. It was the right move, especially since Franken refused to give a straightforward answer to the charges.

Because of her stance, however, progressive megadonor George Soros said she was the only potential Democratic presidential candidate he did not want to succeed. He isn’t the only one who feels that way. Politico reported that “major donors across the country” were angry at her many months afterward.

Remember when Democrats shut down the government last year in a harebrained effort to make Trump agree to give legal status to illegal immigrants who came here as minors? Sen. Amy Klobuchar of Minnesota is probably hoping that primary voters don’t, because she helped bring that episode to an end.

Some activists accused her of betrayal, and MinnPost reported at the time that her role “could come back to haunt her.” Some on the left remain determined that it will.

Rep. Tulsi Gabbard of Hawaii is considered a longshot for the nomination for a lot of reasons. But she added to the list when she called out some of her Democratic colleagues for making an issue out of a judicial nominee’s membership in the Knights of Columbus, a Catholic charitable organization. She opposed the nominee herself, she wrote, but warned against the “religious bigotry” inherent in holding his membership in religious organizations as a mark against confirmation.

Prominent Democrats were outraged. She drew a primary challenger for her House seat soon afterward.

Encouraging education reforms, occasionally siding with Republicans, keeping the government open, maintaining ethical standards, standing for religious tolerance: All of these seem to be black marks in the Democratic presidential primaries.

What seems to be helping Democratic candidates with the primary electorate, on the other hand, is endorsing left-wing fantasies like the “Green New Deal” and indulging in demagogy about tax refunds. The theme of the Democratic primaries so far is that no good deed goes unpunished.

Ramesh Ponnuru is a senior editor at National Review, visiting fellow at the American Enterprise Institute and contributor to CBS News.