(CNN) The House Judiciary Committee voted Wednesday to hold Attorney General William Barr in contempt of Congress, escalating the looming constitutional collision over the Mueller report between congressional Democrats and the Trump administration.

The committee voted along party lines, 24 to 16, to hold Barr in contempt.

This morning before the vote, President Donald Trump asserted executive privilege over special counsel Robert Mueller's report and its underlying evidence, following through on a threat the Justice Department made the night before if the committee moved forward with the contempt vote.The contempt vote and the invocation of executive privilege adds more fuel to the simmering feud between House Democrats and the administration over Democratic investigations . The President has vowed to oppose all Democratic subpoenas, and Democrats have responded by suggesting that the President's obstruction of congressional investigations could prompt them to consider impeachment.

Barr would be the first Trump administration official held in contempt by the Democratic-led House. The matter now moves to the full House for a vote — and then is surely heading to a courtroom showdown between House Democrats and the Justice Department in Democrats' push to obtain the unredacted Mueller report and evidence.

The contempt vote followed a spirited and lengthy debate in the committee, where Democrats warned of a constitutional crisis amid the administration's blockade and Republicans slammed their Democratic colleagues of abusing their power by going after the attorney general.

"This is unprecedented. If allowed to go unchecked, this obstruction means the end of congressional oversight. As a co-equal branch of government, we should not and cannot allow this to continue," House Judiciary Chairman Jerry Nadler said.

"Democrats are angry. They are angry our nation's chief law enforcement officer and his deputy had the audacity to decide the evidence didn't support charges for obstructing an investigation into something the President didn't do," responded Rep. Doug Collins, the top Republican on the Judiciary Committee. "Rather than face the music, Democrats have resolved to neutralize Bill Barr by attacking his integrity and distinguished career."

The Justice Department told the committee just minutes before the hearing on contempt began Wednesday that the President had invoked executive privilege over all the materials that Nadler had subpoenaed.

"Faced with Chairman Nadler's blatant abuse of power, and at the Attorney General's request, the President has no other option than to make a protective assertion of executive privilege," White House press secretary Sarah Sanders said in a statement.

On Tuesday, the committee and Justice Department officials traded offers back and forth as they negotiated to try to stave off the contempt vote. But late Tuesday, the Justice Department sent the committee a letter stating that Barr would ask Trump to invoke executive privilege if the contempt vote moved forward.

"In the face of the Committee's threatened contempt vote, the Attorney General will be compelled to request that the President invoke executive privilege with respect to the materials subject to the subpoena," wrote Assistant Attorney Stephen Boyd.

Nadler responded by saying the vote would be moving forward, accusing the Justice Department of a "last-minute outburst" and urging negotiations over the Mueller report to continue.

"The Department's decision reflects President Trump's blanket defiance of Congress's constitutionally mandated duties," Nadler said in a statement. "In the coming days, I expect that Congress will have no choice but to confront the behavior of this lawless Administration. The Committee will also take a hard look at the officials who are enabling this cover up."

On CNN's "New Day" Wednesday morning, Nadler said that the United States is in a "constitutional crisis."

He added, "We are in one because the President is disobeying the law, is refusing all information to Congress."

A brewing constitutional fight

Practically, holding Barr in contempt is unlikely to change the landscape on the ground -- Republicans used the same maneuver against President Barack Obama's attorney general, Eric Holder -- but it is laying the groundwork for the brewing, multi-pronged court battle between the Trump administration and congressional Democrats.

The Justice Department offered on Tuesday to allow more staffers to view a less-redacted version of the Mueller report that was made available to select congressional leaders, to allow Congress to take their notes from the secure room after reviewing the report and to talk about it among those who had viewed it, according to the Justice Department's letter sent Tuesday evening.

But that didn't hit at the heart of the dispute over the Mueller report, which comes down to two key issues: the grand jury material and Mueller's evidence.

Democrats in their counteroffer requested that the Justice Department commit to work with the committee to go to court to obtain the grand jury material — or at least not oppose the committee's effort to do so, according to a committee spokesman. They also requested a meeting this week to discuss providing the committee access to Mueller's evidence and that the full membership of the Judiciary and Intelligence Committees should be able to view the less-redacted report.

The Mueller report released publicly had approximately 8% of the material redacted, according to a CNN analysis , and the Justice Department offered congressional leaders the opportunity to see a less-redacted version -- with only grand jury material removed, an even smaller percentage. Barr has argued he's not legally allowed to provide grand jury material to Congress.

But Democrats have rejected the Justice Department offer to view a less-redacted report, arguing they are entitled to grand jury material, and Nadler has urged Barr to join him in seeking a court order to release it. Democrats have said they need Mueller's evidence, specifically citing in a letter last week the FBI's witness interviews and contemporaneous notes that witnesses provided to the special counsel's team, which are cited throughout the report.

This story has been updated with additional developments Wednesday.