Sen. Elizabeth WarrenElizabeth Ann WarrenTrump's SEC may negate investors' ability to fight securities fraud Schatz's ignorance of our Anglo-American legal heritage illustrates problem with government Dems ponder gender politics of 2020 nominee MORE (D-Mass.) is heading into coal country.

Warren is slated to campaign for Democratic senatorial candidate Natalie Tennant on July 14 in W. Va.'s Eastern Panhandle. Tennant is challenging Rep. Shelley Moore CapitoShelley Wellons Moore CapitoAt least Alzheimer’s research is bringing Washington together Overnight Tech: Intel chief says 'no doubt' Russia will meddle in midterms | Dems press FCC over net neutrality comments | Bill aims to bridge rural-urban digital divide | FCC to review rules on children's TV Senators offer bill to close rural-urban internet divide MORE (R-W.Va.), who holds about an eleven percentage point lead.

Capito's campaign already criticized Tennant for seeking to campaign with Warren, who supports President Barack ObamaBarack Hussein ObamaOvernight Energy: Dems ask Pruitt to justify first-class travel | Obama EPA chief says reg rollback won't stand | Ex-adviser expects Trump to eventually rejoin Paris accord Overnight Regulation: Trump to take steps to ban bump stocks | Trump eases rules on insurance sold outside of ObamaCare | FCC to officially rescind net neutrality Thursday | Obama EPA chief: Reg rollback won't stand Ex-US ambassador: Mueller is the one who is tough on Russia MORE's carbon emission proposal. Republicans and coal state Democrats say the proposal goes too far and would devastate the coal industry.

"Elizabeth Warren is anti-coal, anti-gun, anti-business and pro-ObamaCare. Everything she stands for is completely at odds with the West Virginia values Natalie Tennant claims to put first," Capito campaign spokeswoman Amy Graham said. "By choosing to align herself with someone like Elizabeth Warren, Natalie Tennant has taken her stunning hypocrisy to a new level."

Sen. Joe ManchinJoseph (Joe) ManchinPavlich: The claim Trump let the mentally ill get guns is a lie Toomey to introduce bill broadening background checks for firearms Scott Walker backs West Virginia attorney general in GOP Senate primary MORE (D-W.Va.) has heavily criticized Obama's policies, dubbing it a "war on coal." Manchin, along with Sens. Heidi HeitkampMary (Heidi) Kathryn HeitkampSenate rejects Trump immigration plan Cramer to announce North Dakota Senate run on Friday Senate Democrats not sold on bipartisan immigration deal MORE (D-N.D.) and Mary LandrieuMary Loretta LandrieuProject Veritas at risk of losing fundraising license in New York, AG warns You want to recall John McCain? Good luck, it will be impossible CNN producer on new O'Keefe video: Voters are 'stupid,' Trump is 'crazy' MORE (D-La.) sent a letter to the administration last year urging Obama to revise the regulations.

When asked point-blank whether he'd want Warren to campaign for him, Manchin smirked and said: "Now that I can't comment on... I can't talk about other people's races."

He continued: "[Tennant will] have to make those decisions on her own. And it depends on what Elizabeth has said. The bottom line is this country cannot run without coal."

Manchin said that Warren would find an audience in West Virginia if "she accepts an all-in energy policy where she accepts that we have to use everything we have and there has to be a balance between the economy and the environment."

The Tennant campaign noted that Manchin supports Tennant.

Tennant, in a statement, looked to align herself with Warren's criticism of large financial institutions.

“This campaign is a clear choice between the West Virginia values I represent and the Wall Street dollars Congresswoman Capito represents," Tennant said in a public statement. "Wall Street banks have too much say over Washington already, West Virginia working families and college students deserve a Senator who will speak up for them.”

Manchin has advocated for the administration to spend more research and development money to invest in newer technology for the coal industry.

"What we should be doing is using research and development money that's been sitting at [the Department of Energy] for the last eight years and no one's used it all," Manchin said. 

"If we were able to use that technology and clean up the climate around the world -- that's what we should be doing because there's going to be more coal used than ever before. If Elizabeth can say that, if she understands that, if she accepts that -- it'd be great," Manchin said.

Warren also supported the recent EPA carbon emission proposal released earlier this month for power plants.

"Scientists all around the world have collected mountains of evidence about the dangers of carbon pollution, and their basic conclusions are no longer speculative or debatable. Even so, some politicians respond to this evidence by denying it is true – by rejecting scientific evidence – or by claiming they just can’t understand the science," Warren said in a June 2 speech on the Senate floor supporting the administration's recent EPA proposal. 

"This country wasn’t built by people who ignored facts," she said. "Sure, the deniers can defend their friends in the pollution business. They can rail against science or pretend it doesn’t exist. But the facts are catching up with us: this pollution is killing people across this country... Let the deniers deny the facts – but don’t let them deny our children clean air to breathe or deny our parents long and healthy lives."

Manchin told reporters in Washington a day later: "You know, we talk about deniers. I would say they're the deniers -- not me... They've got to use coal. They've got to use gas because it provides so much of the energy that we use."

In a statement released through the Tennant campaign, Warren said she didn’t agree with the Democratic candidate on all issues, but that Tennant would fight for coal jobs in West Virginia.

“Natalie and I don't agree on every issue. For example, she has made clear to me that she will fight against EPA regulations that I support if she believes it means protecting coal jobs for West Virginia,” said Warren. “But I strongly support Natalie's campaign because I have no doubt she will work in the Senate to make sure working families have a fighting chance to succeed in this country again."

Warren spokeswoman Lacey Rose did not respond to a request for comment.

“Natalie Tennant supports coal – period," Jennifer Donahue, a spokeswoman for her campaign, said in a statement. "Natalie will stand up to President Obama, the EPA, Harry ReidHarry Mason ReidWATCH: There is no Trump-Russia collusion and the media should stop pushing this The demise of debate in Congress ‘North by Northwest,’ the Carter Page remake MORE and anyone else who tries to undermine West Virginia coal jobs.

Congresswoman Capito is grasping at straws in a desperate attempt to distract from her consistent record of doing Wall Street’s bidding at West Virginia’s expense,” she added.

The Warren, Tennant campaign event will be focused on education.

This story was updated on June 24 at 11:41 a.m.