House Democrats on Monday evening abruptly halted an effort to increase congressional pay for the first time since 2009, saying the proposal would be reviewed carefully after several freshmen Democrats made overt efforts to block it.

Members of Congress generally make $174,000 per year, with senior leaders earning more, and no cost-of-living adjustments have been made in the past nine years. However, vulnerable swing-state Democrats, concerned how the proposed $4,500 pay hike would look if it didn't also have Republican support, had signed onto amendments rejecting the measure.

“It needs more discussion,” House Appropriations Committee Chairwoman Nita Lowey, D-N.Y., told Fox News.

New York Democrat Rep. Alexandria Ocasio-Cortez, meanwhile, told Fox News Monday that the planned $4,500 bonus was simply a cost-of-living adjustment.

"It’s not even like a raise," Ocasio-Cortez said. She called opposition to the pay increase "superficial. ... This is why there's so much pressure to turn to lobbying firms and to cash in on member service after people leave, because precisely of this issue."

Ocasio-Cortez added that both members of Congress and people making minimum wage deserve more money.

“It’s not even like a raise." — New York Democrat Rep. Alexandria Ocasio-Cortez

"It may be politically convenient, and it may make you look good in the short term for saying, 'Oh we're not voting for pay increases,' but we should be fighting for pay increases for every American worker," she said. "We should be fighting for a $15 minimum wage pegged to inflation so that everybody in the United States with a salary with a wage gets a cost of living increase. Members of Congress, retail workers, everybody should get cost of living increases to accommodate for the changes in our economy. And then when we don't do that, it only increases the pressure on members to exploit loopholes like insider-trading loopholes, to make it on the back end."

The Congressional Research Service (CRS) found in May that, adjusted for inflation, salaries for members of Congress "have decreased 15 percent since the last pay adjustment in 2009." Following a cost-of-living adjustment formula established in 2009, members of Congress should currently be making $210,900, the CRS found.

The turnaround on congressional pay was one in a series of dramatic developments during a whirlwind day on Capitol Hill, with many more potentially still to come. In the evening, the Democrat-led House Rules Committee conducted a hearing in which it prepared a resolution for debate Tuesday that would enforce a subpoena via contempt for both Attorney General William Barr and former White House Counsel Don McGahn.

The resolution does not mention contempt by name. But it is, for all intents and purposes, a civil contempt resolution. The full House is expected to vote on the resolution Tuesday.

"I wish we didn’t have to be here today," Rules Committee Chairman Jim McGovern, D-Mass., said at the hearing. "I wish Donald Trump acted more like a president and less like a king. But this resolution is necessary because of his actions and those of his administration."

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The Judiciary Committee, led by chairman Jerry Nadler, D-N.Y., earlier in the day backed off its own effort to hold Barr in criminal contempt. Nadler reached a deal with the Justice Department for access to evidence related to former Special Counsel Robert Mueller’s Russia report, although the precise contours of the arrangement remained unclear.

In a statement, Nadler announced the agreement with the Justice Department to turn over key evidence from Mueller’s investigation pertaining to the review of whether President Trump obstructed justice. Nadler asserted only that the "most important files" would be revealed to members of the committee from both parties.

As of 8 p.m. ET, Democrats said they expected to receive the files shortly.

Nadler's deal with the DOJ came moments before the Judiciary Committee opened a fireworks-laden hearing with Nixon Watergate counsel John Dean. House Republicans lined up to hammer Dean, saying he deliberately obstructed their questioning of former Trump lawyer Michael Cohen earlier this year and pointing out how he's accused numerous Republican presidents of Watergate-like misconduct over the years.

At one point, the hearing room broke out into laughter, as Florida Republican Rep. Matt Gaetz grilled Dean for turning Nixon comparisons into a profitable "cottage industry" for himself.

"Mr. Dean, how many American presidents have you accused of being Richard Nixon?" Gaetz asked.

"I actually wrote a book about Mr. Bush and Mr. Cheney with the title, 'Worse than Watergate,'" Dean responded, prompting loud laughter from the audience.

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The House Oversight Committee, meanwhile, said it will prepare a separate contempt resolution for Barr and Commerce Secretary William Ross over documents and information related to the citizenship question in the 2020 census. That vote is expected Wednesday and relates to Democrats' concerns that the Trump administration included a citizenship question to deter illegal immigrants from filling out their census forms.

Legal experts generally have concurred that under the 14th Amendment, the census constitutionally must count all people in the U.S., including illegal immigrants. Census figures, in turn, are used to calculate how many members of Congress each state is afforded. Democrats, by many accounts, would lose representation in Congress if illegal immigrants were undercounted.

The Supreme Court is currently weighing the legality of the Trump administration's decision to include the census question, following a lawsuit by 18 states against the addition. Justice Ruth Bader Ginsburg, speaking to a meeting of lawyers and judges earlier this week, remarked that "the event of greatest consequence for the current term, and perhaps for many terms ahead" was the resignation of Justice Anthony Kennedy, who was replaced by Brett Kavanaugh.

That comment prompted speculation that the high court would uphold the census question by a 5-4 margin.

The citizenship question was last asked on the census in 1950, but beginning in 1970, a citizenship question was asked in a long-form questionnaire sent to a relatively small number of households, alongside the main census. In 2010, there was no long-form questionnaire.

"There is no credible argument to be made that asking about citizenship subverts the Constitution and federal law," Chapman University law professor and constitutional law expert John Eastman told Fox News. "The recent move is simply to restore what had long been the case."

And yet, more drama remains possible this week concerning the Democrats' spending bills, which were to contain the pay hike for legislators. The rest of the amalgamated spending bill is still expected to be on the floor later this week, funding four of the 12 federal spending areas. The combination measure would fund State and Defense Department operations, Energy and Water programs, as well as the Departments of Labor and Health and Human Services.

The so-called Hyde Amendment, which blocks federal funding for abortion, is customarily a part of the Labor Department-Health and Human Services (HHS) appropriations bill.

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A recent furor over the Democrats' position on abortion -- and votes that former Vice President Joe Biden took over the years supporting the Hyde Amendment -- could derail the bill. Biden last week suddenly changed his decades-long support for the once-bipartisan Hyde Amendment amid pressure from the party's progressive wing.

Biden's communications director, in a testy interview with CNN, struggled to explain why Biden had changed his mind, if not for political expediency.

Fox News' Chad Pergram and Brooke Singman contributed to this report.