National tea party leaders are not backing down from their endorsement of Senate Minority Leader Mitch McConnell, despite pushback from local tea party factions in Kentucky.

Speaking with reporters outside an event that featured appearances by all of the prominent tea-party-backed senators, Scottie Hughes of TPNN.com defended her group’s decision to back the Kentucky Republican. McConnell helped the group organize the event in the Capitol.

Both Hughes’ Tea Party News Network and its umbrella organization TheTeaParty.net have endorsed McConnell, even though he is expected to pick up a tea-party-inspired primary challenger on Wednesday. Local groups in Kentucky have asked the national groups to rescind their support.

“The national tea party doesn’t want to sit here and go against anything a local tea party group says. That being said, however, we need to look to make sure that we’re properly vetting our candidates, which is something the tea party has done very badly in the past,” Hughes told reporters gathered outside the event. “We as a national tea party are encouraging this local tea party group: You need to sit down and vet the candidate you’ve picked, vet his background, make sure that he’s not just coming out as kind of a loose cannon as a tea party candidate.”

Hughes identified previous tea party candidates that weren’t properly vetted, including the 2010 case of Christine O’Donnell in Delaware. O’Donnell upended moderate then-Rep. Mike Castle in the state’s Senate primary only to then flop in the general election.

Hughes appeared to be making reference to Matthew Bevins, a Kentucky businessman
expected to announce a primary challenge
to McConnell on Wednesday in Frankfort, according to the Louisville Courier-Journal.

“Sen. McConnell has been a very strong supporter of us for the past year, and when you look at it, the other thing that the tea party needs to do is we need to win, and we need to make sure that we’re winning with the most conservative candidate,” Hughes said. “We’re getting good candidates who really are going to win, and we want to make sure that they’re not weakened going into the Democratic challenger.”

Hughes argued that conservative dollars might be better spent on a different race than the one involving McConnell. McConnell’s home-state colleague Sen. Rand Paul, who won his seat largely on the strength of the tea party, has also endorsed McConnell and suggested the grass-roots movement should focus on open-seat races rather than primaries against sitting Republicans.

Louisville television station WHAS reported Monday that 15 local tea party groups sent a letter to The Tea Party.Net and Tea Party Nation, asking them to withdraw their endorsement of McConnell.

“Senator McConnell’s Progressive Liberal voting record, his absolute iron fisted rule over the Republican Party in Kentucky and his willingness to roll over and cede power to President Obama and the Liberals in Washington, prove that he is no friend to the American people or the citizens of the Commonwealth of Kentucky,” the letter says, according to WHAS.

The letter also accuses the national tea party organizations of undermining “the work of the real grassroots Tea Party organizations all over Kentucky. Had you taken the time to reach out to us, you would have learned that the Tea Parties in Kentucky do NOT support Senator McConnell’s campaign.”