It evidently registered last week with Minnesota House Republican candidate Nolan West — or his employers in the House GOP caucus — that his history of racist, sexist and homophobic social media comments made him ill-suited to continue his employment as a legislative aide. West resigned from his day job Wednesday after his social media record went public.

But the 25-year-old West’s campaign to succeed retiring state Rep. Tim Sanders of Blaine continues. That brings up a question we would put to Republican leaders at both the State Capitol and in his District 37B: If West’s words disqualify him as a House employee, why would the GOP still consider him qualified to represent 40,000 Minnesotans as a House member?

The Republican Party endorsed West’s candidacy well before news broke about his social media outrages, which include condemnation of the nation’s first Republican president, Abraham Lincoln, and posting “It’s LYNCHING TIME!” after President Obama’s election in 2008. West’s hate-filled words should cause him to forfeit his party’s recommendation. An embarrassed GOP should hasten to withdraw it.

The District 37B GOP is not the only political organization guilty of less-than-rigorous vetting recently. In District 2A in northwestern Minnesota, DFLers appear to have been surprised to learn in July that candidate Jerry Loud was accused of battery and was the subject of a restraining order during a divorce more than 30 years ago.

Two years ago, it was the state GOP’s turn to be embarrassed. It endorsed Supreme Court candidate Michelle MacDonald without knowing that she had been convicted the year before for refusing a blood alcohol test and obstructing the legal process. The party learned from its mistake. MacDonald is on the ballot again this year; the GOP did not offer an endorsement in the race.

Minnesotans habitually have deferred to the judgments of political parties in the selection of candidates for state offices. But that’s a habit that can be broken. When parties fail to screen out unsuitable candidates, public confidence in endorsements erodes — and more primary challenges to party-endorsed candidates are bound to follow.