The House Judiciary Committee announced it will investigate President Trump’s national emergency declaration in light of comments he made at his Rose Garden press conference on Friday morning, during which he claimed that he "didn't need to do this."Details: In a letter addressed to Trump, Democrats who control the committee requested a hearing with White House Counsel Pat Cipollone and "appropriate individuals" from the Justice Department, as well as background documents related to the decision and written responses to a number of questions. The panel asked Trump to provide the relevant information by Feb. 22.The big picture: Trump is already facing a host of legal challenges, including the threat of lawsuits from the ACLU, attorneys general in New York and California, and Democratic leaders Nancy Pelosi and Chuck Schumer. On Friday, Rep. Joaquin Castro (D-Tex.) tweeted that he would introduce a joint resolution to terminate Trump's national emergency.If the House passes the resolution, the Senate would be forced to vote on it — meaning Republicans, many of whom have voiced frustration at Trump's decision, would have to go on the record to express whether they support the president's use of emergency powers.