President Trump’s Republican allies want the Senate to hold an impeachment trial to prove that the president is not guilty of high crimes and misdemeanors. But Democrats in the House are standing in the way.

While the House approved articles of impeachment last December, its Democratic majority has not yet appointed the members who will take those articles to the Senate and manage its case in the subsequent trial there. Until the House takes these steps, the Senate can neither convict Trump nor acquit him, because its rules stipulate that the House must officially inform senators of its decision to impeach the president before a trial can begin.