U.S. President Donald Trump said on Sunday he would nominate Representative John Ratcliffe, a Texas Republican who strongly defended him at a recent congressional hearing, to replace Dan Coats as the U.S. spy chief.Coats, the current U.S. director of national intelligence who has clashed with Trump over assessments involving Russia, Iran and North Korea, will step down on Aug. 15, the president said as he announced his decision on Twitter."A former U.S. Attorney, John will lead and inspire greatness for the Country he loves," Trump said, thanking Coats "for his great service to our Country" and saying that an acting director will be named shortly.The post of director of national intelligence, created after the Sept. 11, 2001 attacks on the United States, oversees the 17 U.S. civilian and military intelligence agencies, including the Central Intelligence Agency.Ratcliffe, a member of the House of Representatives intelligence and judiciary committees, defended Trump during former Special Counsel Robert Mueller's testimony on Wednesday about his two-year investigation of Russian interference in the 2016 presidential election and possible obstruction of justice.Ratcliffe also accused Mueller of exceeding his authority in the report's extensive discussion of potential obstruction of justice by Trump after the special counsel decided not to draw a conclusion on whether Trump committed a crime.The congressman agreed that Trump was not above the law, but said the president should not be "below the law" either.Ratcliffe is a former U.S. attorney and mayor of Heath, Texas, a Dallas suburb. He also worked at a law firm run by former attorney general John Ashcroft, a Missouri conservative.Ratcliffe joined Congress in 2015 after defeating a longtime incumbent and some Republican Party leaders had pushed for him to be named U.S. attorney general last year after Trump ousted Jeff Sessions from that role.The congressman helped lead a congressional investigation into 2016 Democratic presidential nominee Hillary Clinton's use of private email servers and former FBI director James Comey's decision not to recommend criminal charges against her.Sources familiar with the recent history of congressional oversight of the intelligence community said they were not familiar with any particular accomplishments or history that would qualify Ratcliffe for the DNI position.COATS CLASHED WITH TRUMPCoats will join a long list of senior officials to leave the administration since Trump took office in January 2017, either through resignation or firing. The list includes a defense secretary, attorney general, two national security advisers, a secretary of state, an FBI director, numerous top White House officials and assorted other Cabinet members.His departure will mark the second time Trump has parted ways with a former Republican senator named to his Cabinet, after his November 2018 firing of Sessions, who the president faulted for recusing himself from overseeing the federal investigation into Russia's role in the 2016 election.Coats, who has served as director of national intelligence since March 2017, clashed with his boss early on, taking a hard line toward Russia that sharply contrasted with the conciliatory approach Trump pursued toward Russian President Vladimir Putin.In January, Coats told Congress North Korea was unlikely to give up its nuclear weapons, contradicting a statement by Trump that Pyongyang no longer posed a threat.Coats also told lawmakers that Iran had continued to comply with a 2015 nuclear deal with major powers that Trump abandoned in May 2018.The next day, Trump complained on Twitter about "passive and naive" U.S. intelligence leaders, suggesting they "go back to school!"In July 2018, Coats publicly admitted he did not know what happened during one-on-one talks in Helsinki between Trump and Putin that raised concern among many U.S. lawmakers.The White House faced an uproar over several issues from the summit including Trump's failure to confront Putin over American intelligence agencies' findings that Russia meddled in the 2016 U.S. election and Putin's proposal that Russian authorities be allowed to question U.S. citizens.At a post-summit news conference with Putin, Trump responded to a question about Russian meddling in the U.S. election by casting doubt on the findings of his own intelligence agencies and denouncing the "stupidity" of U.S. policies.In an unusual step, Coats responded by releasing a statement firmly supporting U.S. assessments that Russia was involved in "ongoing, pervasive efforts to undermine our democracy."