In his new book, "An Act of Congress," The Post's Robert G. Kaiser writes that Congress "is a ponderous institution, usually cautious and always reactive."

This week should prove Kaiser's point well.

Gay rights supporter Jeremy Pittman hands out flags outside the Supreme Court in March. (Jim Lo Scalzo/European Pressphoto Agency)

Most of the activity this week on Capitol Hill will be across the street from the Capitol at the Supreme Court. The high court is set to rule on 11 pending cases in its final week of the term, with the rulings on four of the cases -- two about same-sex marriage and one each on affirmative action and voting rights -- expected to provoke strong responses from lawmakers.

Pay special attention to how members of both parties respond to the rulings on same-sex marriage -- especially whether Republicans and moderate Democrats join with other political figures who have announced support for same-sex marriage in recent months in anticipation of the rulings.

While we await the rulings, let's check in on the congressional action.

In the Senate

Senators are scheduled to put the finishing touches on a bipartisan immigration measure Monday night by voting to proceed to debate on changes that will expand the legislation to more than 1,100 pages and roughly $50 billion in costs.

Once those changes are added -- in the form of an amendment running hundreds of pages -- the Senate is expected to spend the rest of the week on final debate of the bill.

If you've been keeping score with The Fix's Immigration Whip Count, you know that there's roughly 60 "yes" votes, with several more senators of both parties set to announce their intentions in the coming hours.

Sen. Rand Paul (R-Ky.) and other Republican senators have said they're still opposed to the bill, but supporters believe that the final immigration bill could attract broad bipartisan support — maybe more than 70 yes votes.

Supporters also hope to accelerate debate and hold a vote on final passage by Thursday evening, allowing senators to slip out of Washington beginning Friday morning for the July 4th recess.

Before they leave, keep an eye on whether senators reach an agreement to confirm several pending nominations, including Penny Pritzker to serve as commerce secretary and Anthony Foxx for transportation secretary.

In the House

What's up with the Farm Bill now that a mix of Democrats and Republicans defeated it last week? Good question.

Almost nobody expected that the five-year measure would go down so dramatically, and while the vote raised doubts about the leadership of House Speaker John A. Boehner (R-Ohio) and the GOP's whip-counting operation, there's a more practical concern: What does a prolonged impasse between the House and Senate mean for the nation's farmers and the poor who rely on federal food aid?

Corey Boles of The Wall Street Journal laid out five potential scenarios over the weekend, with the caveat that none of them seems a sure thing:

1. Revive the bill defeated last week, basically by bringing it back up, Boles wrote, "once tempers cool."

2. Increase the bill's $20.5 billion in cuts to food stamp funding even more to win sufficient GOP support -- a move that would infuriate the White House and congressional Democrats and make final negotiations almost impossible.

3. Reduce the bill's cuts in food stamps to win the support of Democrats.

4. Abandon the House bill altogether and hold a vote on the Senate's version of the farm measure, which only cuts food stamp funding by $4 billion.

5. The House could pass a one-year extension of current farm policy and spend another year trying to write a new five-year bill. (This was supposed to happen last year, but the House and Senate failed to reach an agreement then, too.)

No matter what, the clock is ticking: Current federal farm policy runs out on Sept. 30.

As for floor action, the House will hold votes on two energy bills and three naming bills: One, to rename a new bridge in St. Louis for the late St. Louis Cardinals baseball player Stan Musial; another to rename the air traffic control tower in Nashua, N.H. for a recently deceased longtime employee; and a bill to rename part of the Internal Revenue Code after former Sen. Kay Bailey Hutchison (R-Tex.), who authored sections of the act regarding the spousal IRA.

Also, the House Ways and Means Committee is scheduled to hold a hearing Thursday to chart the progress on its investigation of how the Internal Revenue Service improperly targeted certain organizations seeking tax-exempt status.

Follow Ed O'Keefe on Twitter: @edatpost