Manchin gets a GOP challenger

West Virginia Republican Rep. Evan Jenkins announced Monday he will challenge 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.) next year.

Manchin is seen as one of the most vulnerable Senate Democrats in the country, and represents a state easily won by President TrumpDonald John TrumpAccuser says Trump should be afraid of the truth Woman behind pro-Trump Facebook page denies being influenced by Russians Shulkin says he has White House approval to root out 'subversion' at VA MORE in last year's election.

The former governor is also one of the best-known politicians in his state, however, and he has worked carefully to cultivate an independent image. 

That's an image Jenkins will look to attack; on Monday, he argued that Manchin had "changed" since coming to Washington in 2010. 

"Joe changed when he got to Washington. West Virginia values? Not anymore," Jenkins says in an announcement vide on his campaign website.

Jenkins focuses on Manchin's decision to author compromise legislation in 2013 that would have strengthened background checks on gun sales. That bill, which failed in the Senate, is proof that Manchin won't stand up for the Second Amendment, Jenkins said.

"Joe Manchin broke that promise, violating our values and pushing gun control with 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 and the New York liberals," Jenkins says, as footage plays of then-President Obama and others talking about Manchin's work on the bill.

Jenkins is a top recruit for the seat, so his entry will help boost Republican hopes that the party can knock off Manchin. Other Republicans are publicly weighing a bid, including fellow Reps. David McKinleyDavid Bennett McKinleySenators offer bill to close rural-urban internet divide Lawmakers battle Trump, PhRMA on discount drug rule House rejects Democrat's resolution to impeach Trump MORE and Alex Mooney, along with state Attorney General Patrick Morrisey

West Virginia is one of the 10 states where Democrats are defending a Senate seat in a state won by President Trump in 2016.

Republicans are also defending just eight seats overall compared to 25 for Democrats. 

Trump won a larger share of the vote in West Virginia than in any state except Wyoming, a fact Jenkins played up.

"With Donald Trump in the White House, we've got a real chance to turn things around," Jenkins says as video of Trump meeting with miners plays on the screen. 

"He needs our help and I need your help."

This story was updated at 4:29 .m.