The House health care bill took all of ten days to pass, from the day Nancy Pelosi formally introduced the legislation to its historic passage on Saturday. The Senate is slated to take up the bill as early as next Monday, but it’s likely to be a much longer slog. Due to differences between House and Senate rules, there’s plenty on the Senate side that could delay the bill for weeks, or even months, prompting Senate Majority Leader Harry Reid to announce that the final bill won’t pass until Christmas, at the earliest. Here’s a rundown of what needs to happen for the health-care bill to pass in the Senate--and the tactics that its opponents are likely to use to slow down the process:

1) To bring the bill to the floor, the Senate first has to vote on a “motion to proceed.” This will require Reid to have an assured 60 votes, necessary for invoking cloture to override a potential filibuster. The first hold-ups could occur here, thanks to moderates like Ben Nelson, who says he won’t support the procedural motion if an anti-abortion provision like the Stupak amendment isn’t included in the bill.

2) Once the bill is brought to the floor, if it violates any of the spending caps and requirements in the budget resolution that the Senate passed last spring--which is possible, given the kinds of compromises Reid may end up making to appease different Senators and interest groups--then a Republican could raise what's called a “point of order." The Democrats would again need 60 votes to move the debate forward.

3) The process of deliberating the bill's amendments on the floor could then begin. This is where many of the hot-button topics like the public option, immigration, and abortion could jam up the debate. Unlike the procedure in the House, where amendments had to receive Pelosi’s approval to move forward, Reid will not be forewarned of all of the amendments the Senate Republicans will try to put on the table. Republicans, for their part, are expected to bring forward amendments that could force potentially embarrassing or politically contentious votes on Democrats. They might also decide to filibuster any Democratic amendment for which Reid can’t achieve cloture.

4) Reid, for his part, could also resort to more heavy-handed tactics to restrict floor amendments. Depending on how Reid decides to structure and control the debate, up to six amendments can be offered at the same time--the original amendment, a substitute amendment, and two amendments to modify each. If Reid wanted to block the Republicans’ ability to offer up amendments related to one on the floor, he could use his right to preferential recognition as Majority Leader to fill up the “amendment tree” with his own provisions, thus refusing to recognize the other side’s proposals. It’s an unpopular tactic that would likely infuriate the Republicans--who might be more inclined to filibuster or, as Tom Coburn has threatened, read the entire bill aloud on the floor to delay the debate--but it’s one Reid (as well as his Republican predecessors) has employed in the past to defend bills against minority-led obstructionism.

5) Should the Senate bill survive the floor debate, Reid will bring it up for a final vote for passage. If it turns out that the Democrats don’t have the 60 votes they need to pass the bill, they can use the oft-discussed reconciliation measure to pass the budget-related components, leaving insurance regulatory reform to a second bill. Alternatively, Reid could decide to let the Republicans go ahead with a ‘round-the-clock filibuster to show the public just how much the GOP is trying to obstruct the bill, either to gather enough votes to invoke cloture or to drum up more support for using reconciliation.

6) If the bill passes the Senate, it will move to the conference committee, where congressional leaders will stitch together the House and Senate bills into the final piece of legislation. The last step before the bill reaches Obama’s desk? Bringing the legislation back to both the House and the Senate, where leadership would need up to drum up the votes once more. The conference bill doesn't need 60 votes for a motion to proceed--but it can still be filibustered* once it's on the floor of either chamber. 

Update: It’s worth noting that “getting to 60” will require various degrees of heavy lifting from Reid and the Democratic leadership at the different stages of this process. For example, after some initial wavering, moderate Evan Bayh admitted that a vote to bring the health care bill to the floor isn’t equivalent to a vote for the bill itself. Rather, voting for such a procedural motion would be a matter of loyalty to the Democratic caucus, leaving the door open for a filibuster later on. The same might be said for some of the less contentious procedural and cloture votes that don’t touch upon the more politically incendiary issues. That being said, Republicans and recalcitrant Democrats will still have more than enough opportunities to grandstand, obstruct, and delay the process, depending on their particular interests and objectives.

*Added detail about filibustering the conference bill.