Democrats have slammed Republicans for failing to use Congress’s constitutional powers to provide oversight of the Trump White House. The House GOP, rather than digging in on Russia’s role in Trump’s election, investigated the FBI for bias against Trump and its handling of Hillary Clinton’s emails. Democrats understand that their successes in November were, in part, related to issues such as health care and jobs, but also a message from voters that there needed to be a check on Trump and his administration.

What will be the big investigations?

Democrats certainly have a lot from which to choose. Expect them early on to begin a parallel investigation to special counsel Robert S. Mueller III’s probe into allegations of the Trump campaign colluding with Russia. Democrats have already said they intend to subpoena Trump’s tax returns, delve into his financial relationships with Saudi Arabia and Russia, and question potential violations of the emoluments clause, which forbids Trump from profiting from foreign governments. Then, this week’s sudden resignation of Defense Secretary Jim Mattis after Trump’s abrupt pullout of Syria invites inquiries into the administration’s foreign policy.

Who are the faces of congressional oversight and what are their roles?

The incoming chairs of 21 House committees will all be looking for areas to scrutinize Trump and his administration. But there are a few key names who will have much of the glory. At the top of the list is Intelligence Committee Chairman Adam B. Schiff (Calif.) who is going to re-up the panel’s Russia investigation. House Ways and Means Committee Chairman Richard E. Neal (Mass.) will be responsible for seeking Trump’s tax returns. Judiciary Committee Chairman Jerrold Nadler (N.Y.) will be able to investigate all goings-on at the Justice Department and plans to make his first subpoena Trump’s acting attorney general, Matthew G. Whitaker. Financial Services Chairwoman Maxine Waters (Calif.), who has been a Trump target, wants to dig into the president’s finances. Then there’s Oversight Committee Chairman Elijah E. Cummings (Md.), who has broad authority to investigate anything and everything Trump-related, including the migrant family-separation policy, the handling of the hurricanes in Puerto Rico and ethics violations by White House officials.

Will Democrats move to impeach Trump?