Patients wait in line at Nuestra Clinica Del Valle in San Juan, Texas, in September 2012 file photo. A study released on Wednesday finds that immigrants, particularly noncitizens, heavily subsidize Medicare, and that policies that restrict immigration may deplete Medicare's financial resources. Eric Gay/AP hide caption

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A bill proposed by the Senate's Gang of Eight (from left, Jeff Flake, R-Ariz.; Marco Rubio, R-Fla.; Charles Schumer, D-N.Y.; John McCain, R-Ariz.; Lindsey Graham, R-S.C.; Bob Menendez, D-N.J.; Dick Durbin, D-Ill.; and Michael Bennet, D-Colo.) has passed out of committee and is headed for the full Senate. But the fate of the issue in the House is less clear. Alex Wong/Getty Images hide caption

itoggle caption Alex Wong/Getty Images

Republican Sen. Marco Rubio of Florida (left) makes remarks at CPAC 2013 on March 14. Jim DeMint (right), president of the Heritage Foundation, is shown during a news conference on immigration reform on May 6 in Washington, D.C. DPA/Landov; AP hide caption

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American farms like this iceberg lettuce field owned by Duda Farm Fresh Foods outside Salinas, Calif., are facing a dwindling supply of farmworkers from rural Mexico. Kirk Siegler hide caption

itoggle caption Kirk Siegler

Facebook CEO Mark Zuckerberg recently announced the launch of FWD.us, an organization promoting immigration and eduction reform. But it's not the first issue he's taken up. In the past, he's donated money to superPACS, politicians and education. Jeff Chiu/AP hide caption

itoggle caption Jeff Chiu/AP

Sen. Marco Rubio, R-Fla., says talk of a bipartisan agreement among eight key senators working on immigration law is "premature." Susan Walsh/AP hide caption

itoggle caption Susan Walsh/AP

From left, Sen. Jeff Flake, R-Ariz., Sen. Chuck Schumer, D-NY, Sen. John McCain, R-Ariz., and Sen. Michael Bennett, D-Colo, arrive at a news conference after their tour of the Mexico border with the United States on Wednesday in Nogales, Ariz. The senators are part of the "Gang of Eight," a larger group of legislators collaborating on changes to immigration. Ross D. Franklin/AP hide caption

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Sen. Marco Rubio, R-Fla, is among a bipartisan group of eight senators who this week announced a plan to overhaul the nation's immigration laws. Charlie Neibergall/AP hide caption

itoggle caption Charlie Neibergall/AP