Every week that Congress is in session, The Washington Post's Ed O'Keefe previews what's expected to happen in the House and Senate:

Can Congress productively legislate and conduct oversight investigations of a sitting president at the same time? This week will be the test.

Senate Finance Committee Chairman Max Baucus (D-Mont.). (Washington Post)

While two congressional committees hold hearings on the unfolding scandal at the Internal Revenue Service, two other committees plan to continue working on overhauling the nation's immigration laws, which if it succeeds, will be the most significant legislative achievement of the year.

The Senate Finance Committee plans to hear Tuesday from former IRS Commissioner Douglas Shulman, his successor, Steven T. Miller -- who resigned last week -- and J. Russell George, the Treasury Department tax watchdog who investigated allegations of wrongdoing. On Wednesday, Shulman and George will be joined by Treasury Deputy Secretary Neil Wolin at a hearing held by the House Oversight and Government Reform Committee. Still unknown is whether Lois Lerner, who heads the IRS's tax-exempt unit, will fulfill an invitation by the House committee to testify.

Meanwhile, the Senate Judiciary Committee plans to continue reviewing almost 300 proposed amendments to the 844-page immigration proposal drafted by the bipartisan "Gang of Eight." The panel has kept the most controversial topics for this week and observers expect intense debate over how to establish the legal status of roughly 11 million illegal immigrants in the U.S. and how many visas should be distributed annually to high-skilled and lower-skilled immigrant workers.

Another potential flashpoint is the possibility that Judiciary Committee Chairman Patrick J. Leahy (D-Vt.) will introduce amendments to the bill that would offer green cards to the foreign-born partner of a gay U.S. citizen, or only in cases where the gay couple is married. Republicans consider those amendments "poison pills" that would upend the carefully-negotiated agreement, so Leahy may hold off and introduce the bill in the full Senate, where it likely would be defeated.

If Leahy steers the Judiciary Committee to wrap up debate on the immigration bill by week's end, it would be a surprise. It also would set up the full Senate to begin debating the bill when it returns from the Memorial Day recess in June.

In direction contradiction of the bipartisan "Gang of Eight" process in the Senate, the House Judiciary Committee plans to meet Wednesday to review its proposal and determine whether it too closely mirrors the 1986 immigration bill signed by Ronald Reagan that many Republicans believe failed to solve the nation's immigration problems. House Judiciary Committee Chairman Bob Goodlatte (R-Va.) has said he prefers to take an incremental approach to the issue, instead of approving a comprehensive set of proposals, and Wednesday's hearing is clearly designed to raise doubts about the Senate process.

This Week in the Senate

(Sean Stipp/AP)

This week the full Senate plans to spend floor time debating a new five-year Farm Bill. If this sounds familiar, it's because the Senate approved a virtually identical measure last year, only to see it falter in the House. In order to keep federal farm and food aid in place, both chambers approved a one-year extensions of current policy and agreed to restart the debate this year.

The Senate Farm Bill, which cleared the Agriculture Committee last week with bipartisan support, slashes $23 billion in federal spending by ending direct subsidies to farmers, consolidating a host of conservation and rural development programs and cutting roughly $4 billion in the Supplemental Nutrition Assistance Program, more commonly known as food stamps.

The House version of the Farm Bill won't come up for debate in the full House until next month at the earliest. The measure goes farther by slashing about $20 billion alone from the food stamp program, which is a nonstarter for Democrats, who opposed the bill in committee and likely will vote against it in the full House. Regardless, House and Senate negotiators hope to have a compromise worked out before the fiscal year ends in September.

This Week in the House

In the latest example of fulfilling the wishes of the GOP base, House Republicans plan to focus this week on construction of the Keystone XL pipeline. Just as GOP leaders held a vote last week on repealing the 2010 health-care law to permit about 30 Republican freshman lawmakers to weigh in, this week's votes are designed to give those same members an opportunity to say they did whatever they could to approve construction of the pipeline that would run from Canada south to Texas.

So the House will vote Wednesday on the Northern Route Approval Act, a bill that would remove the final decision on the pipeline from President Obama by approving the State Department’s first environmental review of the project as sufficient enough to move ahead with the project.

House lawmakers also plan to vote on a series of veterans jobs bills and a measure to approve unveiling of a statue of Frederick Douglass in Emancipation Hall in the U.S. Capitol Visitor Center.

Don't Forget...

Deputy Solicitor General Sri Srinivasan, who President Obama has nominated to the D.C. Circuit Court of Appeals. (Photo: Department of Justice)

This is the final work week for Congress before next week's Memorial Day recess, meaning there's always a chance senators will cut a deal to approve a few more of President Obama's nominees. There are several awaiting confirmation votes, including Richard Cordray to lead the Consumer Financial Protection Bureau, Thomas Perez to serve as labor secretary, Gina McCarthy to lead the Environmental Protection Agency and Sri Srinivasan, to serve on the U.S. Court of Appeals for the District of Columbia, a key federal court.

Democrats are expected to call for a vote on Cordray this week and might attempt votes on Perez and McCarthy, both of whom face stiff Republican opposition. If votes on any of the nominees fail, then expect more chatter from Democrats and their liberal base about revamping Senate rules to make it easier to approve a president's nominees.

Share your thoughts on the week ahead -- or what Congress isn't doing -- in the comments section below.

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