(CNN) President Donald Trump and his Republican defenders may come to regret that Nancy Pelosi gave them what they wished for.

Putting the House on the record for the first time on impeachment, through the speaker's call for a vote by the whole chamber on procedures , is a highly symbolic step that will challenge the entire Republican critique of the impeachment process.

More crucially, such a vote could make it more difficult for the GOP to dodge the substance of the Ukraine scandal and the issue on which impeachment will turn: Did Trump abuse his power?

Superficially, the House speaker's call for the vote is a reversal and vindicates GOP critics who have blasted her inquiry. But it threatens to begin eroding the central pillar of Trump's defense so far: that the investigation is nothing but an unconstitutional sham that is depriving him of due process.

Republicans are already framing new process arguments, and even top Democrats argue that Pelosi did not give the GOP everything it wanted: Thursday's vote will merely lay out the next steps in the inquiry and is not a formal authorization of an impeachment probe. But the distinction is likely to be lost on the public.

"If they are true to their word, they are getting what they want: We are giving them a resolution that gives an open process," Rep. Ro Khanna, a Democrat from California, told CNN's Wolf Blitzer on Wednesday evening. "So let's see now what excuse they have."

"It's been more than a month and Republicans in Washington still won't answer the simple question: is it appropriate for a President to pressure a foreign country to undermine our elections?" Pelosi tweeted on Monday morning.

It's been more than a month and Republicans in Washington still won't answer the simple question: is it appropriate for a president to pressure a foreign country to undermine our elections?



Every national security expert knows the answer. #TruthExposed pic.twitter.com/TOC3fOTJ3F — Nancy Pelosi (@SpeakerPelosi) October 28, 2019

An unwillingness by Trump and the GOP to provide an answer has already provoked a wild chain of distractions, including Trump calling his critics "human scum" and a sit-in by conservative lawmakers last week designed to thwart testimony from a Pentagon official.

There will be more hyperbole and hijinks to come -- and more testimony. The National Security Council's top Ukraine expert plans to tell the impeachment investigators on Tuesday that he was so troubled by Trump's July phone call with Ukraine's President that he reported his concerns to a superior, according to his opening statement

But the vote will end the quasi-political war over impeachment and lead to a more comprehensive public debate at a grave national moment.

As a matter of procedure, it was unnecessary. As a matter of politics and the national interest, such a vote can offer transparency and integrity to a grave constitutional process.

The debate will consider Trump's pressure on Ukraine to probe 2020 Democratic presidential hopeful and potential political rival Joe Biden, and a conspiracy theory that undermines the idea that Russia interfered in the 2016 US election.

It is likely to focus on whether there is conclusive evidence that the President withheld nearly $400 million in military aid to a nation effectively at war with Russia in a quid pro quo.

And it could begin to focus lawmakers on what will be the ultimate questions before a likely Senate impeachment trial.

Did the President's actions fall within his wide-ranging prerogative to set foreign policy or do they reach the constitutional bar for impeachment and removal from office?

A bluff called?

Many Republicans were quick to gloat about Pelosi's reversal.

After all, as recently as October 15, the speaker had dismissed their complaints , lecturing them that impeachment was not a game and that "we're not here to call bluffs."

But call their bluffs she did, and in the daily scorecard of Washington politics, her decision ranks as a point on the board for the House GOP and the misfiring White House message machine.

"The cow's out the barn," said GOP Sen. John Kennedy of Louisiana. "They're only doing that because of the pressure."

But any "win" Republicans claim from her reversal is likely to be short-lived.

The latest strategic maneuver in a process that has consistently wrong-footed the White House will weaken the "process" defense that Trump has so far used to stigmatize the impeachment drive.

Beset by days of damaging revelations , Republicans charged Pelosi with depriving Trump of fair representation and shutting Americans out of a closed-door bid to trash the 2016 election.

Never mind that the Constitution, and then a federal judge last week , suggested that Democrats were justified in taking depositions from key witnesses out of the public glare.

A public process, with televised hearings, published transcripts of depositions that appear to damage Trump and the mechanism familiar from past impeachments could expose the President.

The thinking in the White House so far has been that the lack of a House vote strengthens the argument that Democrats are abusing their power by lacking a legislative purpose for impeachment.

But sources now acknowledge that the benefits of such an approach will now wane, forcing Republicans to focus solely on defending Trump's actions, CNN's Kaitlan Collins and Pamela Brown reported.

For months, following the release of special counsel Robert Mueller's report into Russian election interference, links between the Trump campaign and Moscow, and the President's alleged obstruction of justice, Pelosi stood firm against a demand for an impeachment inquiry from liberals.

Her swift switch when details of Trump's dealings with Ukraine emerged via a whistleblower report reshaped Washington politics but still threatened to come with substantial political risks.

But as polls show the public becoming more open to impeachment and removal amid leaks damaging to Trump from depositions, the delay in a full House vote begins to make sense.

It may have allowed the politics to catch up with the process and to ease the potential pressure on some of the vulnerable Democrats she needs to safeguard her majority in 2020.

Some of Pelosi's caucus is craving open hearings that could bring comments critical of Trump's conduct with Ukraine -- from the top US diplomat in Kiev, for instance -- out in public in a way they believe will begin to turn the nation against the President.

The House vote could also bolster Democratic arguments that impeachment is a process strongly rooted in law and the Constitution. It may erode any remaining legal basis for witnesses to ignore congressional subpoenas to testify. Already, a judge has called lawyers for the Trump White House, the House of Representatives and impeachment witness Charles Kupperman to court on Thursday afternoon after Kupperman filed a lawsuit last week asking the federal court to decide whether he would need to testify.

And the vote will build upon a federal judge's ruling last week -- that the Democratic impeachment probe was already legal -- and accusation that the Department of Justice and White House are stonewalling.

New GOP process complaints

After weeks of complaining about process, Republicans reacted to Pelosi's change of course by complaining -- about process.

One of Trump's closest House allies, Mark Meadows, a Republican from North Carolina who has been frequently spotted at the White House in recent days, said the speaker's move fell short of historical precedent.

"Unless you have a vote of inquiry on the House floor, a rule vote is certainly not the same thing," Meadows said.

"You know it's not the same thing unless it's an impeachment inquiry vote."

House Republican leader Kevin McCarthy of California argued that the change of course was an admission that impeachment had been "botched from the start."

The intricacies of parliamentary procedure may pale, however, against television pictures of House members showing where they stand on the issue of impeachment. In effect, America will on Thursday see Democrats voting to open an impeachment probe.

Other Republicans complained that it was too late for Pelosi to change course. GOP Sen. Lindsey Graham of South Carolina said that behind-closed-doors depositions had already corrupted the process beyond mending.

"A vote now is a bit like un-ringing a bell as House Democrats have selectively leaked information in order to damage President Trump for weeks," Graham said in a statement.

But he also claimed credit for forcing Pelosi's hand with his own resolution co-sponsored by 50 senators -- meant to show that a two-thirds majority needed to convict Trump in a Senate impeachment trial does not exist.

Not for the first time, however, some Republicans did not quite seem up with the program, expressing hopes -- probably likely to be in vain -- that the drama could become less frenetic.

"It would be great if the House would ... open this process up," Sen. John Thune of South Dakota told CNN. "I think it would be an entirely different conversation we'd be having."

Overall, the vote in the House on Thursday appears to be derogatory to the interests of the White House.

But there are some upsides. At least it will allow the President a mechanism to be represented by his attorneys as witnesses' testimony takes place.

It may offer the White House counsel's office visibility into proceedings about which it was previously dependent on Republican committee members to provide.

The vote may force Democratic members who won last year in the midterm elections in districts the President carried in 2016 to take a tough vote sooner than they had anticipated.

When the hearings go public, pro-Trump Republicans will have the chance to create mischief in the House Judiciary Committee, which has historically struggled to keep them in order.

A House vote will allow strong conservative backers of the President a chance to show their constituents their support in his hour of need. And it will unite the GOP behind him.

Whether all of that is worth the potentially greater price of Trump's conduct being exposed before millions of watching Americans is the crucial question of the coming months.