As frightening a prospect as it is for progressives and liberals and other assorted Democrats, it is now impossible not to contemplate what two years of a Republican-led Senate would be like. While Democrats are still putting on a brave face about their chances in the 2014 midterms ("Our ground game is going to win the day!"), the possibility of Republicans picking up the six Senate seats they now need to gain control of the chamber is very real and even (according to many election forecasters) probable. But what would this mean for President Obama's last two years in office?

What it would mean for Democrats in the Senate would be becoming the minority party. Harry Reid would either become the Minority Leader, or perhaps the Democratic reins would be turned over to someone else in a leadership change (Dick Durbin and Chuck Schumer are the two names most often mentioned in this scenario). But this is merely the most obvious change in the way the Senate works. The big question is what rule changes and tactical changes Mitch McConnell would do once he takes over. Some of these might actually be beneficial to Democrats (McConnell has said he'd open up the "filling the tree" amendment process, for instance, which might mean even in the minority Democrats could get floor votes on their own proposals), but most of course will favor Republicans and their political agenda.

The two biggest changes in the way the Senate operates would be on presidential appointment confirmations and the legislative filibuster. The first of these would come as a result of the seething resentment Republicans still feel about Harry Reid "dropping the nuke" earlier this year (when Reid pushed through a rules change that eliminated the filibuster for all presidential appointees below Supreme Court justices). With one vote, Reid was able to deny Republicans the ability to stop nominations by filibustering all nominees (which they had been doing up to that point). It was a monumental change, and it has allowed many stalled nominees to be confirmed ever since. It will also allow a lame-duck Senate under Reid to hustle through all the nominees they possibly can, before the new Republican Senate takes office in January.

The question is what Mitch McConnell will do about this rule. Republicans hated the change, but are they really -- once gaining the majority -- going to immediately hand power back to the minority party? It would obviously be against their interests to do so, especially considering how favorable the playing field will be in 2016 for Democratic Senate candidates (in other words, McConnell will know for the next two years that a Republican Senate majority may be a very temporary situation). What is much more likely to happen is that McConnell will keep the "no filibuster" rule in place for nominees, and perhaps if Democrats do reclaim power in 2016, change the rule back in the lame-duck session as a protest (Democrats would immediately change it back again when they took power in 2017, of course).

McConnell won't have to worry about filibustering nominees, though, because Republicans will be in the majority and will thus already be able to reject any nominee they don't like. "Any nominee they don't like" is likely to quickly become "all of them," in fact. We could see two years without any new federal judges being confirmed, as well as any executive branch appointees. McConnell could easily do this -- with or without any rule change. Stalling nominees at the end of a president's term is a tactic that has been used by both parties in the past, but McConnell will likely use the tactic to the absolute extreme, by not letting anyone even get to the floor for a vote. Obama will complain loudly, but the public largely doesn't pay attention to this sort of inside-baseball thing in Washington, so McConnell will likely not even pay any sort of political price for doing so.

The other big change will be one of tactics, rather than modifying the Senate's rules. McConnell could "drop his own nuke" and change the rules for legislative filibusters -- jettisoning all filibusters for just about everything (with the only exception remaining for Supreme Court nominees). A simple majority vote would pass all legislation, if McConnell did go nuclear in this fashion. This might seem tempting indeed for Republicans with a very thin majority -- especially since it would be seen as "payback" for Reid's rule change on confirmations. But, again, McConnell knows there is a very good chance Democrats will retake the Senate in 2016, and then Republicans would have to live with not being able to filibuster bills after that point, as a direct result of their own action.

What is much more likely is that everything will magically become a budget issue. Every piece of far-out Republican legislation will be tied -- no matter how tenuously -- to the budget. This will allow the most contentious votes to be "reconciliation" votes, which cannot (by current rules) be filibustered. Remember reconciliation? Democrats used it to pass Obamacare. Republicans certainly have not forgotten this. They'll delight in adding all their pet social issues to the budget, just so they can all be voted on without the pesky Democrats being able to filibuster any of them.

Democrats, since 2010, have been rather timid in the filibuster wars. Reid knew by then that pushing through legislation by reconciliation would, in the end, not achieve much of anything -- since the new Republican House would not agree to any of it. Republicans have filibustered pretty much every piece of legislation more controversial than naming post offices ever since, and Reid has largely allowed them to get away with it. Mitch McConnell is not going to do the same thing, though. For one, he'll have a House run by his own party to work with. For another, Republicans have never been shy about abusing a parliamentary tactic and then, when the political tables are turned, using another parliamentary tactic to not allow Democrats to do the same against them. So look for the effective death of the legislative filibuster, leaving Democrats to cry in their minority wilderness.

One other background change worth mentioning is that Republicans would get control of all the Senate committees. So look for a whole lot more "oversight" hearings (think: what Darrell Issa's been doing in the House -- on steroids). But in the more immediate future, Republicans can be counted on to move quickly on a whole host of their agenda, and the first 100 days of a Republican Senate and House would likely produce all sorts of bills, as the Tea Partiers are given free rein to indulge in some pent-up frustrations. All of these bills will be in the "veto bait" category, however, since President Obama is not going to sign Tea Party fantasies into law. Once the initial wave of silly legislation abates, however, things will get much more serious for both sides.

Mitch McConnell is then going to face the same problem that John Boehner has been struggling with for the last four years: corralling members of his own party to get much of anything done. Think about it -- Boehner's House has not been able to agree on any bills on a long list of conservative issues: a Republican health care reform bill (to replace the hated Obamacare), immigration reform of any type (even just: "Seal the borders!"), and tax reform and/or entitlement reform (this list should in no way be seen as complete, as there are many other items on it). And that's just on their own issues -- the Republican House has also refused to move on any progressive issues, such as increasing the minimum wage; but this is due to ideological reasons and not due to the impossibility of Boehner herding the Tea Party cats. Pretty much every Republican agrees (for instance) that we should beef up the Mexican border, but no bill has made it through the House to do so -- even though Republicans have maintained for years that "a piecemeal approach" is the way to go (in other words: "Secure the border first, pass any other immigration reform later"). Tax reform -- lowering corporate taxes -- has also been a longtime campaign issue for Republicans, and yet Boehner's House has not managed to come up with any sort of plan that could pass even among Republicans. Mitch McConnell is going to have the same problem in the Senate, and it'll be even more acute because his majority is going to be an awfully thin one.

If Republicans wind up with 51 Senate seats next year (just for the sake of argument), then what this means is that every single Republican senator can hold the entire legislative process hostage on any bill. Remember Joe Lieberman and Max Baucus during the Obamacare debate? That's what it'd be like for Republicans. Since McConnell will need every vote to pass a Republican-only bill, even one defection will torpedo the bill's chances. This will leave McConnell at the complete whim of senators such as Ted Cruz. All the time -- on every contentious bill. Even if Republicans get more than 51 seats, it's not going to take many of them to sink a bill's chances. And there are plenty of other "does not play well with other Republicans" type of senators than just Ted Cruz. Senate Tea Partiers may end up wagging the McConnell dog in the same fashion as House Tea Partiers confound Boehner on a regular basis. This is going to make it very hard to get anything done that isn't straight out of the Tea Party playbook.

But, occasionally, things do need to get done in Congress. A Republican Senate is pretty much an iron-clad guarantee of the return of "fiscal cliffs" and "government shutdowns" and "hostage-taking" and all the rest of the budgetary games Republicans are known for playing. Some crucial piece of legislation -- a continuing resolution to keep the government afloat, or raising the debt ceiling -- will approach a deadline. The Tea Partiers will be given an opportunity for grandstanding. President Obama will stand firm. But then, eventually, a deal has to be struck.

What happens at this point is the great unknown when contemplating a Republican Senate for the next two years. The only thing that is virtually assured is that everybody who pays attention to politics is going to be massively disappointed at the end of the day. Such is the nature of compromise. The hard right is going to be apoplectic that they can't force their agenda on the president, and they have shown no tolerance for any incremental gains Republicans might make in such a situation. They'll be convinced that they could get the whole ball of wax by just holding firm enough, and they will not even be impressed with winning 80 or 90 percent of what they're demanding.

Progressives, on the other hand, are likely going to be just as disappointed. Because President Obama is going to be forced to return to how he operated at the beginning of his term -- reaching a hand out to Republicans in the hopes that some sort of middle ground can be reached. The last two years of Obama's term may wind up resembling the final years of Bill Clinton's term, when such things as welfare reform were signed by a Democratic president. Obama will be thinking about "his legacy," and will likely be mindful that "...and then for the next two years, the president vetoed everything and Washington ground to an absolute halt" is not going to be what he wants written about the end of his term by future historians. Like Clinton, Obama may get on board with some ideas that horrify progressives in his own party. One possible example of this might be entitlement reform.

There will indeed be a lot of fallout from Republicans capturing control of the Senate, if it comes to pass two weeks from now. Most of this will not be foreseen, as Republicans will be popping champagne corks without considering the fact that they are now going to be forced to govern, and Democrats will be licking their wounds and putting all their faith in Obama's veto pen -- a faith that may wind up being tragically misplaced. One way or another, two years with a Republican Senate would result in a political wild ride, that's for sure.

-- Chris Weigant

Cross-posted at The Huffington Post

Follow Chris on Twitter: @ChrisWeigant