For supporters of health care overhaul, the process of crafting and passing legislation was never going to be pretty. But President Barack Obama and key stakeholders had hoped it could at least be bipartisan.
Now, after only one Republican supported the House bill and few of them are inclined to endorse the Senate version, the spirit of bipartisanship -- which helped forge nearly every major piece of legislation, from the Civil Rights Act of 1964 to tax policy overhaul in 1986 and No Child Left Behind in 2001 -- appears largely absent from the process.
"We don't believe in bipartisanship just because we think people should be nice to each other," said Jason Grumet, president of the Bipartisan Policy Center, a nonpartisan, nonprofit group that had been urging a bipartisan compromise on health care legislation.
"When you're trying to do something as significant as reorganizing a sixth of the U.S. economy, not only is it hard to adopt that legislation through one party, but it's hard to implement something like that if 40 percent of the Congress is, on some level, wanting it to fail."
While Grumet hasn't lost all hope that a bipartisan solution will be achieved, he says it appears unlikely. "The health care debate has become a complex brew of serious policy differences enflamed by an iconic political testosterone battle," he said.
The partisan divide that has colored much of the debate has been brewing since the start of the Obama presidency and now poses potential complications for a number of major pieces of legislation awaiting consideration by Congress.
Implementation of health care overhaul, climate change legislation and immigration law, among others, could all be imperiled by strictly party-line votes.
With the changing tides of Washington politics, such sweeping, partisan legislation could be susceptible to change, depending on what happens in the midterm elections next year. "I think there certainly will be a sense that it is less-secure policy than would be the case otherwise," Grumet said.
Will Senate Show Bipartisanship on Health Care?
But before health care overhaul becomes law, it has to pass the Senate, where the stage is set for a tough and grueling partisan debate that could drag the process on for months.
Ron Brownstein, author of "The Second Civil War: How Extreme Partisanship Has Paralyzed Washington and Polarized America," attributed some of the partisan rancor to what he calls "the great sorting out."
In recent years, Brownstein said, Democrats have become more purely liberal and the Republicans more purely conservative, eliminating a range of ideologies that used to exist within the parties themselves.
More homogenous parties have been enforced by political interest groups who target defectors, and by gerrymandering, the drawing of congressional district lines to keep a seat solidly blue or red, he said.
The result is that members of Congress are now more reluctant than ever to stray from their party lines and endorse legislative compromise, Brownstein said.
Rep. Steny Hoyer, D-Md., said at Georgetown University in February, "'Bipartisanship' is one of those words that everyone is for -- words like freedom, or security, or happiness -- until we get down to the hard work of defining what they mean. Bipartisanship does not mean that because there are two parties, each party gets to write exactly half of every bill."
But even incorporation of political ideas from both sides of the aisle seems increasingly challenged by party leaders, who often urge their members to adhere strictly to doctrine.
On ABC News' "Top Line" last week, Republican Party chairman Michael Steele issued a warning to Republicans who may consider supporting Democrats' health care bill: "You do not want to put yourself in a position where you're crossing that line on conservative principles, fiscal principles, because we'll come after you," he said.
Democratic leaders have appeared equally entrenched at times. Valerie Jarrett, senior adviser to the president, told ABC News' George Stephanopoulos that Democrats have listened to Republicans' ideas but there are no guarantees they'll compromise.
"[Obama] has reached out," she said on "This Week" Nov. 1. "He has listened. He has reached across the aisle ... [but] that doesn't mean that you actually have to change what you think is in the best interests of the American people simply to get a Republican vote."
Climate Change Legislation: Hope for Bipartisanship?
What's now missing in the health care debate is a pair of strong political leaders to bridge the divide, people such as former senators Bob Dole and Tom Daschle, Grumet of the Bipartisan Policy Center said, who "had moments of significant partisan debate but always found the ability to work together.
"What doesn't work is to show up with a several hundred page bill and say, 'What tweaks do I need to make to get your vote,'" Grumet told ABC News. "I do think that there's going to have to be a decision among Democrats that it is desirable to bring Republicans in at the front end to craft the architecture of these bills."
Grumet said he sees hope for bipartisanship's return to Washington in the early stages of the climate change debate, where Sens. Lindsey Graham, R-S.C., John Kerry, D-Mass., and Joe Lieberman, the independent Democrat from Connecticut, have recently expressed a desire to collectively start the bipartisan process anew.
ABC News' Teddy Davis and Rick Klein contributed to this report.