Conservatives are bringing out the torches and pitchforks for Mitch McConnell.

Long-simmering tension between the tea party and Senate minority leader has again risen to the surface as a swath of conservative activists redouble their efforts to help Kentucky businessman Matt Bevin oust McConnell in the Republican primary on May 20, before he even makes it to the general election.

The lobbying group FreedomWorks, the Jim DeMint-founded Senate Conservatives Fund, the political organization Madison Project and prominent tea party activist Erick Erickson are all trying to tear down McConnell, a 29-year incumbent who is vying to become Senate majority leader next January.

Their latest beef? It’s not just that McConnell isn’t a true conservative — it’s that his poor standing in the polls back home endangers Republican hopes of recapturing the Senate.

Erickson, a Fox News contributor and editor of RedState.com, has made it his personal mission to take down McConnell. He mobilizes his followers with such calls to action: “The single biggest thing you can do to clean up the GOP is to defeat Mitch McConnell in Kentucky by supporting Matt Bevin.” He warns that defeating McConnell is essential to assert the tea party’s dominance over the Republican Party: “[W]hen you beat the sitting Senate Republican Leader in a primary, suddenly Washington knows the grassroots are in charge.”

More recently, Erickson has seized on a series of new polls showing McConnell struggling against Democratic candidate Alison Lundergan Grimes. “Ironically, the GOP may wind up still losing the Senate because of [McConnell],” he wrote on in a blog post on Friday.

FreedomWorks, a wealthy conservative activist group that focuses on on-the-ground organizing, recently endorsed Bevin, calling him a “great upgrade” for Kentuckians. “Now more than ever, we need strong fiscal conservatives who will fight to cut spending on the front lines, not the sidelines,” said the group’s president, Matt Kibbe.

This week, Kibbe pointed to a Rasmussen survey in which Bevin was outperforming McConnell against Grimes. “To beat Grimes in November, we have to ditch Mitch,” he said, deriding McConnell as a “do-nothing incumbent.”

The Senate Conservatives Fund, led by former DeMint chief of staff Matt Hoskins, was an early endorser of Bevin. One month ago, it had already spent about $1 million trying to defeat McConnell. The animus between Team Mitch and SCF’s leadership runs deep and dates back nearly a decade to when McConnell and DeMint feuded in the Senate.

The Madison Project, which supports hard-right candidates, has endorsed Bevin and has even opened up a get-out-the-vote headquarters in Kentucky to boost his campaign. “Polls show that Senator Mitch McConnell (R-KY) is one of the most unpopular incumbents in the country, and voters are starving for new leadership in Washington,” said Madison’s Drew Ryun.

Outside the tea party orbit, the conservative opposition to McConnell is puzzling. A ruthless and efficient political operative, he has done more than perhaps any other Republican to stymie President Barack Obama’s agenda, using innovative tactics like routine filibusters and successfully cracking the whip for total party unity against health care reform. But conservatives have set a high bar, disqualifying him for ostensibly prioritizing his thirst for power over tea party causes and for supporting measures like the Wall Street bailout and bills to keep the government open without drastic fiscal reforms.

McConnell is not to be underestimated. The five-term incumbent has raised at least $10 million, dwarfing Bevin, who has raised only about $900,000. But between the conservatives who are out for blood and his deteriorating standing at home, the Senate Republican leader has a bruising battle on his hands before he can compete to hold on to his seat in the Nov. 4 election.