The case for weighing the impeachment of President Trump boils down to a few simple points: In an effort to win re-election in 2020, Mr. Trump apparently attempted to extort a foreign government into announcing an investigation of his top political rival. The president did so while also trying to revive a conspiracy theory that casts doubt over whether the Russian government interfered in the 2016 election on his behalf. Witnesses have already testified that in order to achieve those goals, Mr. Trump withheld hundreds of millions of dollars in foreign aid against the bipartisan wishes of Congress. All the while, the president and his staff have refused to cooperate with the congressional investigation into what transpired.