WASHINGTON — Sen. Bob Corker, R-Tenn., made waves in August after he issued a tough rebuke of President Trump's handling of the violence in Charlottesville, Virginia. And when he recently met with the president, he admitted that Trump couldn't let this criticism go."I said, 'Mr. President, I stand by what I said,'" Corker recalled in an interview for "Meet The Press.""He said, 'You called me incompetent,'" Corker remembered. "I said, 'Mr. President.' I knew it was coming, right?"He says they spent five minutes on the topic during the Sept. 15 meeting."What I said is he has not yet demonstrated some of the competence and some of the stability," Corker told host Chuck Todd of his August comments. "It might've been in reverse, but not yet demonstrated, and that we need for him to be successful. I mean, the country needs for him to be, the world needs for him to be successful. Look, I stand by those comments."Corker said he does feel new Chief of Staff Gen. John Kelly has brought "an air of discipline" to the White House, and he praised the administration's handling of the hurricanes that hit Texas and Florida. He was impressed with Trump's new strategy for Afghanistan — a country where Corker said the U.S. could likely maintain troops for the next decade.But, he added, "I don't make comments like that without thinking about them."The Tennessee senator announced last week that he won't seek re-election next year, a decision he admitted to struggling with. First elected to the Senate in 2006, Corker worked his way up to chairman of the Foreign Relations Committee, and aimed to forge some relationships with lawmakers on the other side of the aisle while also holding on to his conservative credentials."I told people that I couldn't imagine serving more than two terms," Corker said, adding, "a big part of the enjoyment has been never, ever thinking about a political race. You know, I almost didn't run in '12."Corker felt this decision gives him "15 months of freedom" before he leaves the Senate. "I think I'm going to have more impact over the next 15 months than I've had in the last 10 years," he said.His big announcement came the same day that voters went to the polls in a heated primary runoff between two Republicans in Alabama's Senate race, where Sen. Luther Strange, R-Ala., eventually lost to conservative firebrand Roy Moore.Corker himself likely could have faced a primary challenger in 2018, as frustration across the country has mounted with members of Republican leadership."I think it's more about the resentment that people have towards the fact that they don't see Washington solving problems," Corker said specifically about voters' frustrations with leadership like Majority Leader Mitch McConnell and House Speaker Paul Ryan."You know, the president's helped with that by, you know, mocking the leadership on both sides of the aisle," said Corker. "But I think it was an outgrowth of tremendous frustration with Washington."The timing of Corker's announcement also coincided with the Republican rollout of their new tax plan — a longtime Republican target that seemed all the more pressing after their attempts at repealing the Affordable Care Act repeatedly fell through this year.But Corker placed a very high bar for the tax proposal to get his support."If it looks like to me, Chuck, we're adding one penny to the deficit, I am not going to be for it, okay?" he said. "I'm sorry. It is the greatest threat to our nation. The greatest threat to our nation."He mocked what he called "a party atmosphere" in Congress: "Heck with revenue. Heck with, you know, constraining spending.""So yes, I will remain a deficit hawk until I leave here," he said.