Sen. Chris Murphy (D-Conn.) returned to the Senate floor Monday to call on Congress to pass gun control reforms.

Murphy said that nearly 4,000 people have been killed in the United States by guns since Dec. 14, 2012, when a gunman killed 20 first graders at Sandy Hook Elementary in Newtown, Conn.

Sen. Jeff Sessions (R-Ala.) called on lawmakers to ask critical questions about the immigration bill because he said an influx of new legal workers would drive down wages in America during a time of slow economic growth.

“I urge my colleagues, before we rush out and sign up for an immigration proposal … somebody ask the question what is it doing to recent college graduates as well as low-skilled workers," Sessions said on the Senate floor Monday.

The House this week is expected to again pass legislation creating an advocate for homeless veterans within the Department of Housing and Urban Development (HUD).

The House easily approved the Homes For Heroes Act last year in a 414-5 vote, but the Senate never considered it. This year, House Democrats have again proposed the legislation in the hopes that the Senate will take it up.

Senate Majority Leader Harry Reid (D-Nev.) said the House Republican plan to prioritize federal debt is “totally irresponsible” and would lead to a government default.

“If we pay China but not our troops serving overseas, we're in default,” Reid said Monday. “The Republican approach with default is totally irresponsible. Republicans know this risky measure is a nonstarter in the Senate, and even if it could pass the Senate, which it won't, President Obama would veto it.”

Calling allegations "troubling," Reid says Senate will act if IG report finds need for more investigation.

Rep. David Cicilline (D-R.I.) said Monday that he is "outraged" over reports that the IRS was basing audit decisions on politics, and called on the Obama administration to investigate its actions.

"Among the core principles of our democracy is the idea that the government exists to help all its citizens, regardless of their political beliefs," Cicilline said. "I am outraged to learn that certain members of the IRS may have engaged in a concerted effort to apply political pressure on citizens who were seeking to exercise their First Amendment rights to petition the government."

Rep. Michael Turner's bill would jail and fine IRS workers who discriminate against political speech.

Rep. Dan Kildee (D-Mich.) on Sunday called on the UDSA to help deliver emergency food aid to hundreds of kids who no longer use the school lunch program because their schools have shut down.

Kildee said the Buena Vista School District, just south of Saginaw Bay, closed its schools on May 6 because it could not meet payroll. That decision has kicked more then 400 students out of school, and Kildee said 91 percent of those students receive federal food assistance through free and reduced school lunches.

The Senate starts at 2 p.m., but has no votes scheduled. Instead, senators will have a chance to continue debating S. 601, the Water Resources Development Act, if they wish.

Some may also choose to make comments about the growing scandal about the IRS decision to audit tea party groups. Others may talk about the three nominations up this week, including Secretary of Energy nominee Ernest Moniz.