This Question Is More Important Than Removing Trump

This week, as part of the impeachment trial of President Trump, the Senate will take up the question of subpoenas for witnesses and documents. House managers had previously tried but failed to convince their Republican colleagues to go along with a series of amendments on witnesses and documents.

The vote on witnesses is critical. The testimony of key administration or former administration officials like Mick Mulvaney and John Bolton may be the only remaining hope Democrats have for disabusing Republican senators of their loyalty to Donald Trump before the vote on conviction.

But the vote on witnesses is essential for another reason. The Senate is facing a test of the very issue under consideration in the second article of impeachment, namely Mr. Trump’s obstruction of Congress and the institution’s willingness to rein in a president who is abusing the powers of his office. Regardless of their inclinations on the final vote to remove, every senator should understand the critical nature of this decision for the integrity of the impeachment process, the preservation of congressional authority and ultimately for the rule of law.