Sen. Ben Nelson departed from his party's legislative position more than any other senator in 2010 and parted company with President Barack Obama more often than any Democrat.
In a Congressional Quarterly scorecard tracking last year's voting records, Nelson voted against the majority position of his party in the Senate nearly half the time.
Nelson's 46.4 percent opposition score in what CQ described as a rating of "party unity" easily topped Sen. Evan Bayh of Indiana, who finished second on the Democratic list at 31.9 percent.
On the Republican side of the aisle, Sen. George Voinovich of Ohio strayed most often from the GOP position at 31.7 percent.
Nelson voted against the president's legislative position 25 percent of the time, twice as often as Sen. Russ Feingold of Wisconsin, who finished second among Democratic senators at 12.7 percent.
The CQ voting survey "confirms that I'm an independent voice in the Senate," Nelson said Monday.
"I think the people of Nebraska want someone who represents them and their interests (and) works with people on both sides of the aisle," he said, rather than representing party or partisan interests.
Bipartisan cooperation will be critical this year in a divided Congress, Nelson said. Republicans now command a majority in the House, and the Democratic majority in the Senate has been reduced substantially.
"We need to be able to bridge the gap and bring people together," he said. "I've always been able to work with people on both sides of the aisle."
Once again, Rep. Jeff Fortenberry emerged as the most independent Republican in Nebraska's congressional delegation.
Fortenberry voted with his party's majority 87 percent of the time, whereas Sen. Mike Johanns and Reps. Lee Terry and Adrian Smith all topped the 90 percent mark.
Here are their scores: Terry, 92 percent; Johanns, 93 percent; Smith, 97 percent.
Johanns voted more often with Obama's position than the three House members. The scores: Johanns, 48 percent; Fortenberry, 29 percent; Terry, 29 percent; Smith, 26 percent.
The Senate votes include more than 30 confirmations of presidential nominations not considered by the House.
Nelson said "neither side can sit on the sidelines" in the new Congress that convenes this week now that each party controls one house.
Both parties will have a responsibility to govern, he said.
Nelson is on course to seek re-election in 2012, although a final decision will not be made until later this year.