JACKSON, Miss. — A Republican Senate primary Mississippi is shaping up as a battle between an incumbent endorsed by President Donald Trump and a state lawmaker who is pushing hard against Washington insiders by using Trump's own mantra of "drain the swamp" — even as he criticizes the president.

State Sen. Chris McDaniel is holding an event Wednesday in his hometown of Ellisville, Mississippi, and has hinted strongly that he will announce he's challenging Roger Wicker, who's been in the U.S. Senate for a decade.

Backed by tea party groups, McDaniel came close to unseating Mississippi's senior U.S. senator, Thad Cochran, in a bitter intraparty fight in 2014. At the time, McDaniel positioned himself as the outsider trying to topple the political establishment. The same dynamic would be in play in a race against Wicker.

Tuesday evening, Trump tweeted: ".@SenatorWicker of Mississippi has been a great supporter and incredible help in getting our massive Tax Cut Bill done and approved. Also big help on cutting regs. I am with him in his re-election all the way!"

The Senate race in Mississippi four years ago grabbed national attention after a McDaniel supporter entered a nursing home without permission and photographed Cochran's wife, who was bedridden with dementia. Images of her appeared briefly online. McDaniel said he had no connection to the incident.

McDaniel never conceded his loss to Cochran and filed an unsuccessful challenge saying the Cochran camp had cheated in the primary runoff by courting votes from black people who traditionally support Democrats.

Former state Sen. Merle Flowers of Southaven, who represented a strong Republican area that was carried by McDaniel in 2014, said McDaniel has not endeared himself to Republicans since the 2014 race, while Wicker has been aggressive in preparing for 2018. Flowers served at the state Capitol with McDaniel, but supported Cochran and is helping raise money for Wicker.

"Sen. Wicker will not have to introduce him to people he hasn't seen in a while," Flowers said Tuesday. "In addition, Chris McDaniel left a pretty bitter taste in Republicans' mouths at the conclusion by filing the court challenge dragging the GOP through the mud."

Jeri Ausbon, a paralegal who lives in the Jackson suburb of Brandon, voted for McDaniel in 2014 and said she will support him again.

"We need some new blood in there rather than the dyed-in-the-wool Republican Party members, and that's what Roger is and Thad Cochran is," Ausbon said. "It's very hard to run anybody against the establishment Republicans in Mississippi because they have so much power and so much money."

Candidates' filing deadline is Thursday, and the primary is June 5.

Republican officials say a businessman and political newcomer named Richard Boyanton, who lives in Diamondhead, has filed qualifying papers.

McDaniel faces a much different environment in 2018, and a more engaged candidate in Wicker.

Wicker, wary of McDaniel from his challenge of Cochran, has taken an aggressive stance early on. Cochran was accustomed to winning with little effort and took months to engage in the primary.

Wicker preemptively announced in January that 65 top Trump supporters in Mississippi, including county organizing chairmen and chairwomen, had thrown their support to Wicker, all while McDaniel has maintained a steady drumbeat of criticism of the president and his accomplishments.

McDaniel, who backed Texas Sen. Ted Cruz for president, continued his criticism of Trump since the election by questioning his economic credentials and specifically railing against the tax cut, Trump's chief legislative accomplishment. In November, he called the tax cut "an embarrassment" and "smoke and mirrors," according to McDaniel's Facebook posts.

Wicker in 2016 led the National Republican Senatorial Committee, which raised money for candidates nationwide. He had more than $4.1 million in his own campaign account at the end of 2017. Wicker has received $5,400 from Vice President Mike Pence's political action committee, Great America Committee. He was endorsed last week by former Pennsylvania Sen. Rick Santorum, who rallied social conservatives when he ran for president in 2012 and 2016.

McDaniel is poised to receive financial backing from a super PAC called Remember Mississippi, which takes its name from the slogan McDaniel supporters adopted after what they saw as his railroading by the political establishment in 2014. The group raised nearly $1.1 million last year, with $500,000 coming from Richard Uihlein of Illinois, a packaging company executive who has donated to anti-union causes, and $500,000 from billionaire investor Robert Mercer of New York, who had a financial stake in Bretibart News, a website that has been both pro-Trump and pro-McDaniel.


Associated Press writer Thomas Beaumont in Des Moines, Iowa, contributed to this report.


Follow Emily Wagster Pettus on Twitter: http://twitter.com/EWagsterPettus .