House Democrats are set to begin their long-promised oversight of President Trump this week, with several moves centered around the investigations of his alleged Russia ties.

The House Intelligence Committee is expected to vote Wednesday to provide special counsel Robert S. Mueller III with all interview transcripts from its Republican -led probe of Russian interference in the 2016 presidential election. Chairman Adam B. Schiff (D-Calif.) has openly questioned whether witnesses lied to congressional investigators in deference to Trump — and believes Mueller’s office is best positioned to determine whether anyone should be held accountable.

On Friday, Trump’s former lawyer and fixer Michael Cohen, who already pleaded guilty to lying to Congress, is due to provide private testimony before the panel . Lawmakers want him to clarify the timeline by which Trump and his associates pursued a real estate project in Moscow, and to answer questions about Trump’s finances and his campaign’s outreach to Russian sources.

Cohen’s lawyer Lanny Davis declined to comment Tuesday when asked whether his client would comply.

And the House Judiciary Committee is scheduled to hear public testimony Friday from acting attorney general Matthew G. Whitaker as part of its probe of circumstances surrounding Mueller’s investigation. Democrats have challenged Trump’s surprise appointment of Whitaker after the ouster of Jeff Sessions as attorney general last year, and they have questioned whether Whitaker — who had publicly derided Mueller’s probe before taking the job — would limit or compromise the investigation.

House Democrats are expected to scrutinize various Trump administration policies this year, including those on border security, student loans and weapons deals with Saudi Arabia. At every turn, lawmakers are expected to question whether Trump, or those close to him, stood to gain politically or financially from the positions he has adopted.

President Trump listens during a meeting on trade talks last week. (Al Drago/Bloomberg)

But the opening salvo of their Russia-focused inquiries is a chance for lawmakers to change course after two years of Republican leadership they have said they feel was focused more on sparing the president than scrutinizing him.

Over the past two years, several witnesses close to Trump refused to answer the questions panel members posed to them. Democrats frequently complained that GOP leaders were letting witnesses get away with evasion and potential perjury, and not exerting enough effort to follow up. Even in some cases where witnesses appeared under a subpoena, they refused to comply — claiming that conversations with or concerning Trump were too private to discuss, even if the president had not or could not claim executive privilege to silence parts of their testimony.

Anticipating a potential continuation of this trend, the House Judiciary Committee took early steps to dissuade Whitaker from following the same pattern. Last month, Rep. Jerrold Nadler (D-N.Y.), the panel chairman, sent Whitaker a letter, instructing him to give the committee advance notice of any plans Trump might have to invoke executive privilege; on Tuesday, he announced plans to draft subpoenas for Whitaker’s testimony in advance of his hearing to have on hand and ready to deploy in case the acting attorney general refuses to answer lawmakers’ questions.

Republicans have not been on board with Democrats’ anticipatory moves.

“When did we start subpoenaing witnesses who come in voluntarily? The majority had enough faith in its witnesses last week not to subpoena them. The key difference today is simply that this witness is part of the Trump Administration,” Rep. Douglas A. Collins of Georgia, the ranking Republican on the Judiciary Committee, said in a statement. “The message to witnesses here is, if you make the time and effort to appear of your own accord, Democrats are going to subpoena you anyway.”

Left in the minority, the GOP has limited tools to steer the Democrats off the course they are charting.

In the short term, Democrats face potential limitation from the yet-unknown timeline of the Mueller probe — and potentially the witnesses themselves.

Lawmakers have pledged to “deconflict” their inquiries from Mueller’s probe, the completion of which is of paramount importance to congressional Democrats. That could complicate the panels’ efforts to compel witnesses cooperating with that investigation to discuss what they know, if the information is at all relevant to Mueller’s probe.