Conservative grassroots activist Andy Ogles announced he is a candidate for the Republican nomination for the U.S. Senate seat currently held by Senator Bob Corker (R-TN), the Associated Press reported on Thursday.

Ogles, who has been the head of Americans for Prosperity-Tennessee since 2013 and served as the national deputy director of Newt Gingrich’s 2012 Presidential campaign, is now the only announced candidate who will be competing in the August 2018 Republican primary.

“A spokeswoman for AFP said Ogles has stepped down from the organization,” the Tennessean reported.

Two-term incumbent Senator Corker, first elected to the U.S. Senate from Tennessee in 2006, recently stated he has not decided whether he will seek a third six-year term in the 2018 election.

Corker has drawn the ire of President Trump for his unrelenting criticism of the president, who remains very popular in Tennessee, which he won by a 61 percent to 35 percent margin over Hillary Clinton in 2016 while carrying 92 of the state’s 95 counties.

Ogles, in contrast, launched his campaign with a vigorous statement of support for the Trump agenda.

“We will not change the results we are seeing in Washington until we send new, strong conservative representatives to Washington. Our problem isn’t the shortage of Republicans in the Senate, it is the shortage of the right Republicans in the Senate,” Ogles noted in his announcement.

Last month, Corker claimed Trump has not demonstrated the stability or competence to be successful. In May he said that the Trump Administration was in a “downward spiral” and needed to get itself under control.

Trump responded to Corker’s August criticism with a tweet on August 25: “Strange statement by Bob Corker considering that he is constantly asking me whether or not he should run again in ’18. Tennessee not happy!”

Earlier this week, Politico reported that former Trump chief strategist and current Breitbart Executive Chairman Steve Bannon is reportedly encouraging primary opposition to five incumbent Republican Senators, including Corker.

Corker, however, has claimed that he has no reason to believe he is being targeted by the Trump administration.

“I’ve always expected that if I run, that I’ll have a primary. I have no indications whatsoever that the administration would encourage that … We see no evidence of it,” Corker said on Monday.

“I have no reason to believe the administration would encourage a primary. None,” he added.

Corker has significant financial resources in his campaign accounts–estimated to be in the range of $7 million. Polling in Tennessee reportedly indicates he has serious vulnerabilities, however.

Ogles has at least two significant challenges in front of him in the immediate future: raising money and increasing his name recognition in the state.

In addition, Ogles may not be the only candidate to challenge Corker in the race, should he decide to run for re-election to a third term.

State Senator Mark Green (R-Clarksville), Rep. Marsha Blackburn (R-TN-07), and former State Rep. Joe Carr (R-Lascassas) are all reportedly considering a challenge to Corker.

In August Green made headlines when he told Breitbart News that he had directly expressed his disapproval to Senator Corker of Corker’s criticisms of President Trump:

On the same day President Trump blasted Senator Bob Corker (R-TN) for his recent “outrageous” criticisms, State Senator Mark Green (R-Clarksville) tells Breitbart News that he told Corker exactly what he thinks about those comments.

“I’ve already told Senator Corker my thoughts about his comments about the President and that’s as far as I intend to go at this point,” Green told Breitbart News on Friday.

Green announced in early August that he did not intend to run against Corker in 2018 based on how “everything sits right now.”

Asked whether recent events, including Trump’s tweet on Friday, have sufficiently altered the political landscape for him to reassess how things “sit,” Green declined to comment.

“Andy Ogles is a Franklin native with deep family roots in Tennessee dating back to the founding of the state,” according to his campaign website:

Andy studied Political Science at MTSU and graduated with a Bachelor’s degree. He’s had a successful career as an entrepreneur and has used his considerable experience in the non-profit sector. Andy and his wife, Monica, live on a farm in Middle Tennessee with their three children, Adley, Drew, and Isaac.