Director of National Intelligence (DNI) Dan Coats will step down and President Trump will appoint Rep. John Ratcliffe, R-Texas, to replace him, the president tweeted Sunday.

Saying it was time to start a new chapter, Coats wrote in his resignation letter “I have ensured that we have the capabilities necessary to protect against those who would do us harm.” Coats pointed toward his efforts to boost security, restructure the intelligence community (IC) and install new leadership to ensure the president has “the best, most timely, and unbiased intelligence possible.”

Just last week, the DNI named Shelby Pierson, the agency’s election security crisis manager during the 2018 midterms, to the newly created Intelligence Community (IC) Election Threats Executive (ETE) position.

Coats, a strong advocate for election security, has often been at odds with Trump, who has been critical of the intelligence community, questioning its assessment of Russian interference in the 2016 presidential election. Ratcliffe took an aggressive stance in questioning former Special Counsel Robert Mueller last week – at one point contending that the former FBI director’s report on the Russian probe had been written by “Hillary Clinton’s de facto legal team.”

Sen. Chris Coons, D-Del., speaking with NPR’s Morning Edition, called Ratcliffe “a blind loyalist to the president” and expressed concern over how intelligence would be affected.

“I would like to thank Dan for his great service to our Country,” Trump tweeted.