The current partisan divide is as stark and nasty as any in recent history and on almost every issue — from health care to energy independence to reviving the economy — there's little or no effort to find common ground.
But fierce political battle is also a tradition ingrained in American history. If today's hostile environment is particularly intense, it's downright genteel compared to many battles of the past.
The Civil War, when anti- and pro-slavery forces split the nation, is the most extreme example. But there's also the beginning of the 20th century, when the country was becoming more urban and trust-busting Teddy Roosevelt was redefining the role of government.
The current economic troubles have collided with President Barack Obama's efforts to change government amid waves of public anger and protest movements like the tea party.
The angry mood was so discouraging for Indiana Sen. Evan Bayh that the Democrat recently said "I do not love Congress" as he announced he would not run for re-election.
His sentiments have been heard before.
Party politics, President George Washington said in his farewell address in 1796, "agitates the community with ill-founded jealousies and false alarms." It "kindles the animosity of one part against another (and) foments occasionally riot and insurrection."
After two centuries, the nation continues to ignore its founding father's message.
"We've had partisanship ever since we've had federal government," Senate historian Donald Ritchie said. "Bipartisanship is really the exception to the rule."
Partisanship got off to a raucous start in the presidential election of 1800 when the incumbent, John Adams, a Federalist, faced his vice president, Thomas Jefferson, a Democrat-Republican. Adams' supporters portrayed Jefferson as a libertine who would bring French Revolution-style anarchy to the country. Adams was branded a monarchist and characterized as toothless and senile.
The election's repercussions were deadly. Jefferson beat Adams, but under the electoral system at the time the House had to decide between Jefferson and his running mate Aaron Burr, who received the same number of electoral votes. Federalist Alexander Hamilton helped sway the vote to Jefferson, a source of personal animosity that led to a duel in 1804 where Burr shot and killed Hamilton.
But it wasn't until the 1830s — when populist Democrats led by Andrew Jackson took control of the government — that party politics as we know it today really began to take shape, says Sarah Binder, a political science professor at George Washington University. Jackson's opponents referred to him as "jackass," often credited as the source of the donkey as the Democratic Party's symbol.
Binder said waves of partisanship tend to coincide with major changes to the nation as a whole.
The most dramatic example came in the middle of the 19th century. In 1856, Republican abolitionist Sen. Charles Sumner, in a Senate speech, accused a Democratic colleague, Andrew Butler of South Carolina, of taking an ugly mistress, "the harlot, slavery." Rep. Preston Brooks of South Carolina, Butler's relative, entered the Senate chamber and beat Sumner with a cane, nearly killing him.
The redefinition that developed under Teddy Roosevelt became even more pronounced during the Depression, when Franklin Roosevelt's Democrats and the Republicans debated big government and fought over the creation of Social Security.
The golden age of bipartisanship, to the extent it existed, came in the 1940s through the 1960s, when politicians united behind World War II and the Cold War and neither party had a clear-cut ideology. Democrats had their Northern liberals and Southern conservatives, while the GOP was divided between Goldwater Republicans and Rockefeller Republicans.
That all began to change with the civil rights movement and the Republican takeover of the South. After that, said Ritchie, "the Democrats became the liberal party and Republicans the conservatives. There just aren't that many people in the middle who can be persuaded to break rank."
The Congressional Quarterly, which tracks voting trends, says that in 2009 both House and Senate Democrats voted with their party 91 percent of the time on votes where the two parties were at odds. That was at or near record levels of unity for both. House and Senate Republicans were nearly as unified.
That's a sharp contrast to 1968, when only 51 percent of Senate Democrats backed their party on so-called party unity votes, or 1970, when only 56 percent of Senate Republicans fell in line with their party position.
"Clearly you see the country moving into rival camps much more readily and that filters through to the Congress in a hurry," said Sen. Ron Wyden, D-Ore., who has served in the House and Senate for nearly three decades and is known for working well with Republicans.
In the 1980s, he said, there were sharp philosophical differences but it was still possible for President Ronald Reagan and his main antagonist in Congress, House Speaker Tip O'Neill, to work together on Social Security reform.
Voters are disgusted that the two sides increasingly are unable to work together, Wyden said. But he acknowledged it's not going to change until more voters convey that to their representatives in Congress.
According to Wyden:
"It's a lot easier for people to say, 'Look I'm going to go with my partisan friends and try to avoid the shrapnel.'"
On the Net:
Senate history: http://tinyurl.com/cnojdp
House history: http://tinyurl.com/33wyu5
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