It’s worth addressing each of these challenges in turn.
First, there is nothing magical about a House vote authorizing an impeachment inquiry. The administration’s letter calls it a “necessary authorization,” but that’s simply false. A vote isn’t required by the Constitution, federal law or the rules of the House of Representatives. The White House is basing its demands for a vote solely on the fact that a similar vote was held by the House during the impeachment proceedings for Presidents Richard Nixon and Bill Clinton. But in those cases, the votes were necessary to equip the inquiries with additional investigative authority, such as expanded subpoena power; subsequent changes to House rules make that step unnecessary.
From the Democrats’ perspective, there are several reasons not to hold a full floor vote. Most significant, Speaker Nancy Pelosi wants to avoid a situation in which the House leadership is conceding that the White House can dictate any of the terms of how an impeachment is conducted, and what sort of process counts as “legitimate.” Once the House makes that concession, the White House will again move the goal posts, undermining Congress’s role as a coequal branch with the authority to manage its impeachment inquiry.
Ms. Pelosi also wants to protect Democratic members who represent more conservative districts from having to take a difficult vote that might come back to haunt them in 2020. This isn’t a very compelling rationale, especially when those same members will almost surely be called upon to vote on articles of impeachment soon enough.
Finally, Ms. Pelosi knows that Mr. Trump has no intention of cooperating with an impeachment inquiry, even if it were authorized by a vote. Instead, he would use what would likely be a party-line vote to further disparage the inquiry as a partisan hit job.
On Wednesday, Mr. Trump was asked whether he would cooperate if the House held a vote authorizing the impeachment inquiry. “Yeah, that sounds O.K.,” the president said. “We would if they give us our rights.” Of course, Mr. Trump also said he would be happy to speak under oath with the special counsel, Robert Mueller.
And yet it may be a mistake for the Democrats to proceed much further without an authorization by the House. For one thing, a vote would strengthen Congress’s hand in any litigation arising out of the inquiry. A federal judge in Washington, Beryl Howell, said on Tuesday that having such a vote on record would make it “easier” for her to step in and make a ruling on House demands for documents or testimony.
Second, a resolution in support of the inquiry could also lay out specific ground rules, which could enhance the legitimacy of the inquiry in the minds of Americans.