Sen. Mitch McConnellAddison (Mitch) Mitchell McConnellSenate passes 0B defense bill Overnight Health Care: New GOP ObamaCare repeal bill gains momentum Overnight Finance: CBO to release limited analysis of ObamaCare repeal bill | DOJ investigates Equifax stock sales | House weighs tougher rules for banks dealing with North Korea MORE (R-Ky.) sought to emphasize his Tea Party ties Monday by signing papers to file for reelection with Sen. Rand PaulRandal (Rand) Howard PaulSenate Dems hold floor talk-a-thon against latest ObamaCare repeal bill Overnight Defense: Senate passes 0B defense bill | 3,000 US troops heading to Afghanistan | Two more Navy officials fired over ship collisions Lawmakers grapple with warrantless wiretapping program MORE (R-Ky.).

In a video released Tuesday, McConnell is shown signing his filing papers with Paul and state Agriculture Commissioner James Comer (R), who are both Tea Party favorites in Kentucky.

McConnell, long a target of grassroots conservatives, is facing a primary challenge from businessman Matt Bevin, who has already won the backing of some prominent national conservative groups.

The incumbent has been working to shore up support on his right flank for months. He won Paul's endorsement and has emphasized conservative causes, like the Balanced Budget Amendment. McConnell voted against a two-year budget deal approved by Congress last month. 

In the filing video, titled “United,” Paul touts McConnell's work as GOP leader in the Senate.

“What he has done, and what allows him to be the most powerful Republican up there is that he can pull people together,” Paul says. “United on ObamaCare. United for a Balanced Budget Amendment.”

Paul’s comments answer another attack McConnell is facing from his left flank, where he’s up against Democrat Alison Lundergan Grimes: that his leadership abilities have waned and his seniority in the Senate has made him out of touch with Kentucky. 

Meanwhile, Lundergan Grimes' campaign sought to contrast her positions on access to childcare with McConnell's, part of an ongoing effort from the campaign to compare the two candidates on the issues.

Her campaign touted the candidate's proposal to offer tax breaks for businesses that provide on-site childcare for working women, up against McConnell's support for Rep. Paul Ryan's (R-Wisc.) proposed budget, which Democrats say would slash funding for childcare in the states.

--This piece was updated at 4:30 p.m. to reflect Lundergan Grimes' campaign's comments.