By Lauren Fox, Ashley Killough, Ted Barrett and Kristin Wilson, CNN

(CNN) -- Republican leaders believe that Gina Haspel will be confirmed to be the next director of the CIA, though a few notable lawmakers -- red state Democrats and Republican Sens. Jeff Flake and Lisa Murkowski -- are still undecided.

Last week, Arizona Republican Sen. John McCain announced his opposition to Haspel, a factor that is weighing on Flake and others.

But over the weekend, Haspel's supporters got a large boost once Indiana Democratic Sen. Joe Donnelly said he would support her nomination -- joining West Virginia Sen. Joe Manchin as the second Democrat to do so. While Donnelly's decision does not assure Haspel's confirmation, it does help solidify the numbers needed to get her through the chamber. Expect more senators to make their decisions public this week.

Flake said he has "always shared McCain's views on the issue" of torture and added that he believes McCain's statement will "affect everyone."

Some lawmakers are urging the Department of Justice to release a document from John Durham, the federal prosecutor who was tapped to investigate the destruction of the tapes in 2008 and closed the case in 2010 without bringing any charges. The report is a look at how tapes of the enhanced interrogation program were destroyed, but right now it is only available to members of the Senate Intelligence Committee. Virginia Sen. Mark Warner, the top Democrat on the committee, has called on the Justice Department to release the document for all senators to review.

The vote on Haspel in the Senate Intelligence Committee could come this week with a full Senate vote potentially before the end of the month.

'Discharge petition' for immigration solution

Immigration will be back in the spotlight as a group of House Republicans seeks to buck GOP leadership by using a procedural maneuver to force a vote on four competing immigration bills with a procedural maneuver known as a discharge petition.

With the likely help of all Democrats, the group thinks they can get enough Republicans on board to get the number of signatures needed -- a majority of the House -- to trigger floor votes.

Republicans had 18 signatures by the end of the week and need at least seven more to feel confident that they have the numbers. House Speaker Paul Ryan dismissed the effort Thursday, saying none of the four immigration bills will get the President's signature.

"I would like to have an immigration vote before the midterms, but I want to have a vote on something that can make it into law," he said. "I don't want to have, you know, show ponies."

But if Republicans cross the threshold of signatures, it would prompt a heated immigration debate on the House floor that was previously unexpected this year.

Cabinet secretaries on the Hill

Scott Pruitt, the embattled administrator to the Environmental Protection Agency, will return to Capitol Hill this week to testify before a Senate Appropriations Committee about the fiscal year 2019 budget for his agency.

Pruitt, despite a continuous stream of reports and allegations of financial improprieties and the subject of more than 10 separate federal inquiries into his activities, appears to still enjoy the support of the President, who reiterated his confidence in Pruitt late last week.

Department of Homeland Security Secretary Kirstjen Nielsen will appear before the Senate Homeland Security and Governmental Affairs Committee to testify on her department's budget for the next fiscal year, just a week after a contentious Cabinet meeting at the White House, when she and President Trump reportedly had, according to a source, "angry and heated" disagreement over the President's belief that his DHS Secretary isn't doing enough to secure the border.

Russia meddling hearing

The Senate intelligence committee will hear from several marquee former intelligence officials -- James Comey was invited but isn't confirmed -- about a January 2017 Intelligence Community Assessment on Russian meddling in recent elections.

The hearing is part of the committee's investigation into alleged election interference by Russia.

Former director of National Intelligence James Clapper, former CIA director John Brennan and former director of the National Security Agency Mike Rogers are scheduled to appear.

Farm bill

Also on the docket in the House is a five-year farm bill, a massive piece of legislation that sets the eating and farming policy in the United States, including what the US grows and how much the government spends in the process, for about five years. The last one was signed by then-President Barack Obama in 2014.

Democrats are expected to oppose the bill due to stricter work requirements tied to the SNAP program, while it's unclear at this point whether Republicans have enough votes within their own ranks to pass it.