WASHINGTON — When Sens. Bernie Sanders and Amy Klobuchar arrived as freshmen senators in January 2007, they entered a Senate that was very different from the one in which they serve as 2020 presidential frontrunners.

Back then, the Senate moved legislation on the floor and roll call votes on amendments were not a rarity. The amendment voting records of Sanders, a Vermont independent, and Klobuchar, a Minnesota Democrat, show some substantial differences that they have held in their Senate careers.

The distinctions are perhaps most clear when the Senate has considered amendments championed by Republican senators.

Using the CQ Roll Call database of Senate floor votes, here are five amendments on which Klobuchar and Sanders split.

English as national language

During the 2007 floor debate on the immigration bill most associated with GOP Sen. John McCain and Democratic Sen. Edward M. Kennedy, the new senators Klobuchar and Sanders split several times, including on Oklahoma Republican James M. Inhofe's amendment to Kennedy's substitute text. The Inhofe amendment would have declared English as the national language of the United States. Klobuchar voted yes. Sanders voted no.

FISA lawsuits

Another clear area of disagreement over the years has been government surveillance powers and the limits of the Foreign Intelligence Surveillance Act. In 2008, the senators voted on an amendment from Sen. Arlen Specter of Pennsylvania (who was still a Republican at that point) that sought to substitute the federal government as the defendant in lawsuits against telecommunications companies alleged to have participated in the National Security Agency's warrantless surveillance program. Sanders backed the amendment, while Klobuchar opposed it.

Fairness doctrine

Sen. Jim DeMint, R-S.C., offered an unrelated amendment to Washington, D.C., voting rights legislation in 2009 that would bar the Federal Communications Commission from reinstating a rule known as the "fairness doctrine," which required broadcasters to air discussions of controversial views and present opposing viewpoints.

The amendment also would have barred requirements for programming quotas or guidelines on issues of public importance. Klobuchar voted in favor of the amendment. Sanders opposed it.

Gun ownership by veterans

During a contentious 2013 gun policy debate, Sanders voted for a Republican amendment from Sen. Richard M. Burr of North Carolina that would prevent veterans who are mentally incapacitated, deemed mentally incompetent or experiencing an extended loss of consciousness from being deemed "a mental defective," a classification that would bar them from gun ownership.

Under the Burr proposal, no veteran would be blocked from owning guns unless a court finds that the individual posed a danger to himself or others. Klobuchar opposed the amendment.

The third Democratic senator still running for president, Sen. Elizabeth Warren of Massachusetts, came to the chamber in 2013. She also voted against the Burr amendment.

Export-Import Bank

In 2015, senators sparred over reauthorization of the Export-Import Bank, voting on an effort by Sen. Richard C. Shelby, R-Ala., to kill an amendment offered by Republican Sen. Mark S. Kirk of Illinois that would reauthorize and amend the Export-Import Bank charter through 2019.

Kirk wanted to cap the total amount of loans made available at $135 billion for fiscal years 2015-2019.

Sanders voted with Shelby to kill the amendment. Klobuchar and Warren both opposed the motion, effectively supporting the bank reauthorization measure.

(George Levines contributed to this report.)