Opinion writer

* Sam Stein has the most amazing story of the day, on how nobody has bothered to do opposition research on Donald Trump yet:

Multiple Republican campaign sources and operatives have confided that none of the remaining candidates for president have completed a major anti-Trump opposition research effort. There are several such efforts being run by outside conservative organizations. But those efforts are still gathering intel on the businessman after having started late in the primary season, these sources told The Huffington Post. And they worry that it may come too late.

“It is one of the many ways we underestimated him, I suppose,” conceded one top Republican campaign official whose candidate has since exited the race.

But hey, the guy’s probably squeaky-clean, right?

* Speaking of which, here’s an interesting story of the kind I’m guessing we’ll be seeing more of:

Donald J. Trump’s Mar-a-Lago Club in Palm Beach describes itself as “one of the most highly regarded private clubs in the world,” and it is not just the very-well-to-do who want to get in.

Since 2010, nearly 300 United States residents have applied or been referred for jobs as waiters, waitresses, cooks and housekeepers there. But according to federal records, only 17 have been hired.

In all but a handful of cases, Mar-a-Lago sought to fill the jobs with hundreds of foreign guest workers from Romania and other countries.

In his quest for the Republican presidential nomination, Mr. Trump has stoked his crowds by promising to bring back jobs that have been snatched by illegal immigrants or outsourced by corporations, and voters worried about immigration have been his strongest backers.

But he has also pursued more than 500 visas for foreign workers at Mar-a-Lago since 2010, according to the United States Department of Labor, while hundreds of domestic applicants failed to get the same jobs.

I look forward to his defense. “Romanian housekeepers? The best. They’re winners, just terrific, top-notch.”

* Adele Stan argues that Donald Trump has stripped away the coating of moralism from contemporary American conservatism to get down to its chewy center of rage.

* M.J. Lee reports that Rubio’s campaign is preparing for a brokered convention, which is another alternative to winning any primaries.

* Peter Beinart looks at the numbers and concludes that Rubio’s claim that Trump has a “ceiling” is a pipe dream that doesn’t account for the true nature of Trump’s appeal.

* New polls today found that Rubio is behind Trump in Florida, and Robert Schlesinger points out that the fact that Rubio has to devote serious resources to his home state reveals his weaknesses in the larger context of the March voting.

* A new Monmouth poll shows Trump and Hillary Clinton with comfortable leads in Virginia.

* A Clemson University poll shows Clinton leading Sanders by 50 points in South Carolina, which seems like a lot.

* Daniel Larison says Trump is (weirdly enough) significantly more reasonable than Rubio is when it comes to the Israeli-Palestinian conflict.

* Olivier Knox reports that a group of 19 retired generals and admirals supporting Hillary Clinton is blasting the GOP candidates for supporting torture.

* Michael Cohen argues that the stakes of the 2016 election are so astronomically high, and the possibility of President Trump so real, that voting for Bernie Sanders is simply too dangerous a risk to take.

* Simon Rosenberg explains why the early turnout numbers and other factors should lead Democrats to take Trump much more seriously as a viable general election candidate.

* Kyle Kondik provides a handy reference to all the upcoming primaries and caucuses.

* Clifford Young and Chris Jackson look at some new national polling and assess Trump’s chances of winning the GOP nomination at 90 percent.

* Hillary Clinton tells Jonathan Capehart that she regrets using the word “superpredators” back in the 1990s.

* At The Week, I explained the seven things Republicans will say to themselves to rationalize the fact that Trump is their nominee.

* And Trump pledges to Pat Robertson that anyone he appoints to the Supreme Court will be “pro-life,” “very conservative,” and basically just like Samuel Alito and Clarence Thomas. Good to know.