At its simplest level, the impeachment of President Donald Trump looks like a collision between the legislative and executive branches of government. In that fight, each side is trying to defend its prerogatives as it sees them: For Congress (or at least the Democratic-led House), this includes the power to appropriate foreign aid, and the power to conduct oversight; for the executive branch, this means the power to make foreign policy as it sees fit, and to protect its internal deliberations.

What is missing from this portrait is the crucial role of the third branch of government, the judiciary, which has powerfully shaped the impeachment process by declining to exercise its prerogatives, rather than defending them. By choosing to treat the current moment as business as usual, federal courts have effectively removed themselves from the process. In effect, that has dictated what arguments can be mounted in the impeachment fight and what witnesses Congress, and the public, can hear?narrowing and obscuring the case against Trump.

None of this absolves Democrats of the decisions they’ve made. The House majority could have chosen to fight in court to compel testimony from current and former administration officials, especially former National Security Adviser John Bolton. Those fights would not have been resolved in time to hold an impeachment vote before Christmas, but that deadline is self-imposed and politically motivated. Democrats could have waited, or they could have pursued the court battle while also charging ahead.