One of the consistent themes during Joe Biden’s campaign for president and since he won and was inaugurated has been a desire to find bipartisan agreement with Republicans on his agenda items.“The American system contemplates that there has to be cooperation to get most things done,” said Chris Edelson, assistant professor in the School of Government at American University.The false claims by former President Donald Trump that the election was stolen and the votes by Republicans in Congress casting doubt on the election “creates a special challenge for President Biden, and one with no easy solution,” he added.“Joe Biden spent 36 years in the Senate and has a very warm relationship with the body and a veneration for it,” said Norm Ornstein, emeritus scholar at the American Enterprise Institute. “During the campaign and since his election, he said that he believes he can find Republicans to work with. The initial picture is not as rosy.”If the Democrats hold majorities — slim as they are — in both Houses of Congress, why do they need Republicans to get things done?FilibusterMajority parties almost always get their way in the 435-seat House of Representatives. That is because the rules are written to favor the majority party.In the Senate, long-standing rules protect the minority party’s voice. The filibuster is one such rule. It allows a minority of senators to prevent a vote on an issue by continuing to debate it.Senate rules require three-fifths of the Senate — 60 senators — to vote to end the debate.The way the Senate stands now, 10 Republicans need to agree with all 50 Senate Democrats just to hold a vote to get much of Biden’s agenda enacted.But there are rules to allow Biden and Democrats to get around the filibuster:   reconciliation.ReconciliationReconciliation is an arcane process that dates to the 1970s, allowing legislation to bypass the filibuster, as long as it deals with budget issues.This includes raising or cutting taxes and changing priorities for government spending.Senate debate for a reconciliation bill is limited, with just a simple majority needed to pass. With Vice President Kamala Harris presiding, Democrats hold the tiebreaker in the split Senate.Reconciliation has its limits. It can only be done once per fiscal year and could leave out key Biden goals like immigration reform and passing a new voting rights act.Kill the filibuster?Preserving the filibuster is so important to Senate Minority Leader Mitch McConnell that he held up passage of an organizing resolution seeking a promise that Democrats would not use their slim majority to get rid of it.Democrats Joe Manchin of West Virginia and Kyrsten Sinema of Arizona have indicated they will not vote to eliminate the filibuster.While Biden has been quiet about it lately, Republicans tweeted part of his Senate speech from 2005, in which he said the filibuster “is not about stopping a nominee or a bill, it is about compromise and moderation.”But as vice president, Biden saw the filibuster used to thwart President Barack Obama’s agenda and be a useful campaign tool.“When the filibuster was used over and over in 2009 and 2010, in the next midterm election, Republicans won more seats in the House than they had in 100 years,” Ornstein said. “And then after Obama won reelection, it was used again. And in the midterm that followed, they won back the Senate. So, their game plan that’s to obstruct has worked in the past, and it’s likely they’re going to try it again.”Biden navigated those rules of the Senate for 36 years. How he plays by them now will test the success of his presidency.