WASHINGTON (AP) — The Senate is becoming nearly as rancorous as the House, and many say one reason is an influx of senators who served in that sharp-elbowed lower chamber. Tuesday's elections may leave the august Senate with more former members than ever from the rough-and-tumble House.
That fresh Senate injection of lawmakers schooled in the House's combative ways, along with other factors that have added to the capital's political polarization, could complicate efforts by Congress and President Barack Obama to strike compromises during his final two years in office.
The Senate was designed to coax partisan consensus by giving individual senators more power to disrupt, thus creating an incentive to find middle ground. One tactic has been filibusters, procedural moves that let disgruntled lawmakers slow or scuttle legislation and nominations.
Angry over what they consider excessive Republican delays and political gamesmanship, Democrats who now control the Senate have allowed fewer votes on amendments and weakened the filibuster. That's made the chamber more like the House, where rules usually let the majority party reign supreme and snubbing the minority is common.
"It's become more House-like — more partisan, less informal cooperation across party lines, less formal cooperation," said Gary Jacobson, political science professor at the University of California, San Diego. "It doesn't work well in a system where you have divided government because it makes it much easier for there to be stalemate."
Last fall, Democrats muscled through changes that let a simple majority of senators end filibusters of most nominations. The previous threshold was 60 votes, which Democrats could not reach without GOP support.
Filibustered legislation and Supreme Court nominees still face 60-vote hurdles. But the change infuriated Republicans and further frayed bipartisan bonds, and deepened the chill between Majority Leader Harry Reid, D-Nev., and Minority Leader Mitch McConnell, R-Ky.
"When we could do more bipartisan things, we were more productive," said Sen. Patrick Leahy, D-Vt., whose four Senate decades make him the chamber's senior member.
There are 51 senators from the House. The peak was 53 between 2005 and 2007, according to Senate Historian's Office records dating to 1899.
There could be up to 54 senators with House pedigrees when the new Congress convenes in January.
Having a House background doesn't ensure polarizing behavior. Many senators from the House, from veteran Sens. Thad Cochran, R-Miss., and Ron Wyden, D-Ore., to newcomers Martin Heinrich, D-N.M., and Dean Heller, R-Nev., are not viewed as unyielding partisans.
Indeed, some of the Senate's most discordant figures never served in the House, including conservative Sen. Ted Cruz, R-Texas. The tea party movement and the growing clout of outside ideological groups are why some senators seem to relish confrontation and spurn compromise.
"All they do is give impassioned speeches that are the road to nowhere," said former Sen. Olympia Snowe, R-Maine, a moderate who retired in frustration in 2013 and is now senior fellow at the nonprofit Bipartisan Policy Center.
Countered Sen. David Vitter, R-La., a former House member, "If you don't stand up and fight for something, you just end up with the status quo."
Many who say former House members have helped intensify Senate partisanship point to the 1980s and 1990s. That's when Rep. Newt Gingrich, R-Ga., who later became speaker, prodded his party to be more bellicose and engineered a 1994 GOP House takeover that ended four decades of Democratic majorities.
Gingrich helped make Republicans "much more confrontational," said Sean Theriault, University of Texas political science professor and author of "The Gingrich Senators: The Roots of Partisan Warfare in Congress."
Theriault said House Republicans brought their combativeness to the Senate and found "Democrats more than willing to meet them on the battlefield. So it's an all-out partisan war."
Messages for Gingrich at Gingrich Productions, his media company, went unreturned.
Sen. Roy Blunt, R-Mo., a House colleague of Gingrich, said if former House members were hindering Senate performance, "the only House member who really matters there is the all-important House member, Harry Reid."
Reid, a frequent GOP target for his iron control of his chamber, served two House terms and joined the Senate in 1987. He became majority leader in 2007.
Democrats weakened filibusters after Republicans began using them more frequently, which each side blames on the other's inflexibility and focus on seeking politicized votes to fashion into campaign attack ads.
Reid spokesman Adam Jentleson said today's Republicans "just want to get attention for themselves by grandstanding."
Fifty-four current senators have been in that body six years or less. That means more than half the chamber never experienced the more consensus-driven Senate of years ago, when figures such as Sens. Bob Dole, R-Kan., and the late Edward Kennedy, D-Mass., could wage partisan battles but then find compromise.
"Most of them don't know what a properly functioning Senate looks like," said Sen. Lamar Alexander, R-Tenn.
McConnell has said if Republicans win Senate control Tuesday and he becomes majority leader, he will allow more free-wheeling votes and take other steps to make the Senate "better than it is."
Yet should the GOP capture full congressional control for the first time in Obama's presidency and with the 2016 presidential and congressional elections looming, McConnell's fellow Republicans may not want to cede additional leverage to Democrats.