For weeks now, President Trump and Republicans on the Hill have been denouncing the Democratic impeachment process as unfair and even illegal.

The problem, they insisted, was that Nancy Pelosi had greenlighted the closed-door hearings without asking the House to actually authorize an impeachment inquiry. While there was nothing in the Constitution or in House rules that required this, it was an effective argument, because the leaking of private depositions was starting to smell unfair.

But now that Pelosi has unveiled a Halloween surprise, saying the House will vote on the inquiry on Thursday, Republicans are treating it as a bad trick. They say they will oppose the vote that many of them had been demanding.

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Minority Leader Kevin McCarthy: “We will not legitimize the Schiff/Pelosi sham impeachment.”

White House spokeswoman Stephanie Grisham said Pelosi was “finally admitting what the rest of America already knew — that Democrats were conducting an unauthorized impeachment proceeding, refusing to give the president due process, and their secret, shady, closed-door depositions are completely and irreversibly illegitimate.”

Key word: Irreversibly.

Since the old process was a travesty, they say, it has tainted the new process, which is what they said they wanted.

Does it sound like demanding a vote was a useful talking point until the moment Pelosi agreed to such a vote? It’s hard to escape that conclusion. The latest round gives a boost to those who say that when it comes to the Ukraine probe, many Republicans are largely arguing process rather than substance.

The speaker, who is ready to move toward public hearings, wrote to colleagues that she wants to “eliminate any doubt as to whether the Trump administration may withhold documents, prevent witness testimony, disregard duly authorized subpoenas or continue obstructing the House of Representatives.”

One reason Pelosi held off is that some moderate Democrats in swing districts didn’t want to cast what would be seen as an early pro-impeachment vote. But perhaps the party is feeling more confident after the recent hearings.

The latest witness, testifying yesterday, is Alexander Vindman, the top Ukraine expert on the National Security Council. He is also a lieutenant colonel who was wounded by an IED in the Iraq war and awarded a Purple Heart.

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And he was on the famous July 25 call between Trump and Volodymyr Zelensky.

In his opening statement, first leaked to the New York Times, Vindman says: “It is my sacred duty and honor to advance and defend OUR country, irrespective of party or politics.”

Two weeks earlier, upon learning that to get a Trump meeting Ukraine would have to “deliver investigations into the 2016 election, the Bidens and Burisma,” Vindman says he told Trump ambassador Gordon Sondland that his statements “were inappropriate, that the request to investigate Biden and his son had nothing to do with national security, and that such investigations were not something the National Security Council was going to get involved with or push.”

After the Zelensky call, Vindman says, he expressed his concerns to the NSC’s top lawyer because “I did not think it was proper to demand that a foreign government investigate a U.S. citizen, and I was worried about the implications for the U.S. government’s support of Ukraine.”

The lieutenant colonel, who was born in Ukraine and emigrated to the U.S. at the age of 3, quickly drew flak from the president, who tweeted that he is “today’s Never Trumper witness.”

Former GOP congressman Sean Duffy, now a CNN contributor, said on that network: “I don’t know that he’s concerned about American policy, but his main mission was to make sure that the Ukraine got those weapons. He has an affinity I think for the Ukraine.” That is an accusation of dual loyalty against Vindman, who tried to get the military aid to Ukraine unfrozen.

John Yoo, a former Bush Justice Department official, said on Fox last night: “Some people might call that espionage.” He was referring to a passage in the Times piece saying Ukrainian officials sought advice from Vindman on how to deal with Rudy Giuliani, who was leading the effort to dig up dirt on the Bidens. Vindman was reflecting what he thought was the official White House position. And that makes him a spy? (Yoo later said he had been misconstrued and that he meant the Ukrainians might be engaging in espionage.”)

Liz Cheney, the congresswoman who backs an aggressive foreign policy, said it was “shameful” that some are “questioning the patriotism” of people like Vindman.

Once Pelosi pulls off her Halloween surprise, with its inevitable party-line vote, perhaps Americans will get to see witnesses such as Vindman and decide for themselves. The Democrats think they have a compelling case, but it hasn’t been exposed to sunlight, let along cross-examination.