WASHINGTON — Any honeymoon President Donald Trump expects after his second State of the Union address Tuesday is proving to be short lived, as newly empowered House investigators make their first significant moves to scrutinize his administration and advance special counsel Robert Mueller's investigation.

Barely 12 hours after the president’s admonition against "ridiculous partisan investigations” in his speech, the Democrat-led House Intelligence Committee voted Wednesday morning to send thousands of pages of materials to Mueller related to its own yearlong Russia investigation.

The Judiciary Committee, meanwhile, is readying what would be the first congressional subpoena of a high-ranking Trump official, as the panel that would initiate impeachment proceedings against Trump prepares to grill acting Attorney General Matt Whitaker on Friday.

And the House Oversight Committee, with broad jurisdiction to investigate Trump, his businesses and the conduct of administration officials, will hear testimony on what one witness calls an “ethics crisis” in the administration that “jeopardizes not only public trust in government but also national security.”

Those and other committees this week will also conduct oversight hearings on climate change, gun violence, the president’s tax returns, the impact of the government shutdown, and the administration’s Mideast and immigrant family separation policies.

The timing of these House hearings is more coincidence than by design. The Intelligence Committee, for instance, just held its first meeting Wednesday because Republicans only appointed their members last week. And Trump’s State of the Union was originally meant to be two weeks earlier, delayed because of the government shutdown that largely crowded out the House agenda for its first month.

But the president who just last week mused “no venue that can compete with the history, tradition and importance of the House chamber” is now facing head-on what it means to have a branch of government in the hands of his political opponents.

“When he ran, [the president] should’ve known that we are all under scrutiny, and that we all have to be accountable,” House Oversight Committee Chairman Elijah Cummings, D-Md., said Wednesday morning. “It’s a new day."

As promised, Democrats on the Intelligence Committee in one of their first acts voted to send Mueller and his team the full, unredacted transcripts of more than 50 witness interviews that the panel conducted in 2017 and 2018 for its Russia probe. Republicans who led the committee in the last Congress blocked Democrats’ attempt to do so last September.

Democrats say that giving Mueller’s team access to the transcripts could at the very least allow them to determine whether perjury charges are warranted against some of the former Trump campaign and administration officials who appeared before the committee, including Steve Bannon, Hope Hicks, Corey Lewandowski and the president’s son and son-in-law, Donald Trump Jr. and Jared Kushner.

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Chairman Adam Schiff, D-Calif., told NBC News last week that it was his understanding that Mueller’s team has already had access “to the substance of the transcripts,” but would only be able to act on any leads they provided after the committee vote.

Republicans under former Chairman Devin Nunes, R-Calif., ended the committee’s Russia probe last March, concluding based on their work that while some Trump campaign officials took “ill-advised” meetings with Russians, there was no evidence of collusion between both sides to affect the outcome of the election.

Schiff says he intends to continue pursuing leads the GOP cut off, especially on potential financial leverage the Kremlin may have had over Trump.

On Wednesday, he announced that his committee’s work would expand beyond just Trump-Russia ties, but to look at any other “foreign actors” who might have worked to influence the president, his family or associates or to impede any investigations of the president.“

"The American people have a right to know, indeed have a need to know, that the president is acting on their behalf,” Schiff told reporters Wednesday. “We will be conducting our investigation to make sure that the country is protected. We will be doing so in concert with other committees.”

In response to Schiff's announcement, Trump said the chairman is "just a political hack, trying to build a name for himself," and said the move amounted to "presidential harassment."

A spokesman for Nunes, who remains the panel’s top Republican, preemptively accused Democrats of prolonging an investigation for political benefit.

“The Democrats have made it clear their overriding purpose in this committee is to investigate every aspect imaginable of Trump’s life, whether it’s in our jurisdiction or not, in hopes of finding something to serve as a basis for impeachment,” Jack Langer said. “Of course, it seems unnecessary since they claimed two years ago to already have more than circumstantial evidence that the Trump campaign colluded with Russia.”

The Judiciary Committee on Wednesday was holding the first House hearing on gun violence in almost a decade, as it considers new legislation to expand background checks for gun purchases.

But the first real sparring with the GOP came in response to an announcement by chairman Jerry Nadler, D-N.Y., on Tuesday that he would initiate the subpoena process ahead of Whitaker’s scheduled appearance Friday. Nadler said in a statement that he hopes a subpoena is not required to compel testimony, but called it a prudent step given the track record of Trump administration officials appearing before Congress.

“For the first two years of the Trump administration, Congress allowed government witnesses to dodge uncomfortable questions. That era is over,” he said. “If he appears on time and ready to answer [our] questions, the subpoena will be entirely unnecessary.”

Republicans who only a week ago praised Nadler for promising a more transparent subpoena process blasted the move. Ranking Member Doug Collins of Georgia said subpoenaing witnesses who were appearing voluntarily would be “setting a dangerous precedent.”

Kurt Bardella, a former spokesman for the House Oversight Committee under former Republican Chairman Darrel Issa, said Nadler’s move was an indication of the very new environment the Trump administration faces with Democrats in control of key committees.

“Now, it’s not just what happens the day of the hearing and what they say under oath. It’s how does the information that the committees can obtain afterwards line up to what they said, and can it be used against them,” he said. “The stakes are now much higher.”

No current administration officials will appear before the Oversight Committee this week. A scheduled public hearing with Michael Cohen has been indefinitely postponed, while his private interview before the Intelligence Committee was rescheduled Wednesday for Feb. 28.

But Walter Schaub, the former director of the U.S. Office of Government Ethics, will say in testimony submitted in advance of a hearing Wednesday that Trump “has not even tried” to address potential conflicts of interest between his role as president and his private businesses — underscoring what is expected to be a main area of focus for the committee.

“The momentum of four decades of ethics reform came to an abrupt halt on Jan. 11, 2017,” Schaub will say. “The integrity of a nation is at stake.”

The Oversight Committee features some of each party’s fiercest partisans, including several new high-profile Democrats.

“A lot of what we need to do is be aggressive in making up for the lack of oversight that has been going on in the last two years,” Rep. Alexandria Ocasio-Cortez, D-N.Y., told NBC.