As an occasional guest on Saturday Night Live several decades ago, Al Franken would seemingly morph into Pat Robertson, nailing with eerie precision the religious right leader's smarmy unctuousness - a tour de farce that rivals Tina Fey's take on Sarah Palin in the mimicry hall of fame.

But the comic Franken is gone now, at least for the next six years. Thanks to a long-expected ruling yesterday by the Minnesota Supreme Court, and a swift decision by Norm Coleman to finally wake up to reality and stop wasting Republican money in a futile cause, Franken is now free to don the cloak of senatorial seriousness. He did it yesterday, while addressing the issue of whether he views himself as the 60th Democratic senator and thus the guy who gives Democrats their first potentially filibuster-proof chamber since 1979. Without a glint of amusement, he said that, no, "that's not how I see it. (I am) going to be the second senator from the state of Minnesota, and that's how I'm going to do my job."

But since Franken is likely to be a reliable soldier for Barack Obama - particularly during the impending Senate battles over health care reform, climate change, and the Sotomayor court nomination; and, in all likelihood, during subsequent battles over whether to repeal Don't Ask Don't Tell, to enact path-to-citizenship immigration reform, and to enact reforms making it easier for labor unions to organize - it's worth dwelling briefly on the significance of the Democrats' political victory. They dearly wanted to get 60 Senate seats and put themselves in a position to choke off Republican blockage, thus erasing one of the GOP's few remaining power options...and now they've gotten what they wanted.

But, as the saying goes, be careful what you wish for.

The expectations of success have just been ratcheted upward. From this point forward, if Senate Democrats screw things up, if they fail to move the key planks in Obama's policy agenda, they will no longer be able to make excuses. They won't be able to say, well, we simply didn't have the 60 votes to get things done. They own the chamber now, and that could potentially wind up helping the GOP during the 2010 election season. Republican candidates might be able to highlight perceived flaws in Democratic landmark legislation and claim that their own hands are clean. ("Hey, folks, don't blame us!")

But 2010 is a long way off. The immediate impact of Franken's ascent is that the expectations for Democratic success have been sharply raised. Liberal activists, in particular, have spent the last 20 hours insisting that Obama and the Senate Democrats now have a rare opportunity to stiff the nay-saying Republicans and bring on the changes sought by the '08 electorate.

It would not be a shock if this scenario fails to play out.

For starters, two Democrats (Ted Kennedy and Robert Byrd) are ailing, and therefore not necessarily available in the clutch. And there's nothing inherently magical about having 60 seats anyway. It's pivotal only if every single Democrat (plus the two Dem-leaning independents) sticks together, thereby providing the required votes to stop any GOP filibuster. The problem is, Democratic senators generally don't all stick together.

This is partly due to the realities of Senate culture; the place is populated by independent-minded egotists who are often more attuned to the economic interests back home than to the political priorities of their own president. Case in point: Democrat Ben Nelson of Nebraska has fought an Obama plan to overhaul the federal college loan program, because one of the big lenders that benefits from the status quo is based in Nebraska.

And in addition to Nelson, there are at least five other Democrats who hail from traditional red states that voted for either John McCain in 2008 or George W. Bush in 2004, or both. Mary Landrieu of Louisiana, for instance, staunchly opposes any health care reform bill that would create a public option; indeed, liberal activists are now running TV ads against her, citing the fact that she has collected $1.6 million in campaign donations from the health and insurance companies. Meanwhile, both Arkansas Democratic senators, Blanche Lincoln and David Pryor, have been notably unenthusiastic about Obama's proposed health care reform and his landmark bid to cap greenhouse gases.

Unless Obama can somehow twist arms in the tradition of Lyndon Johnson, it's hard to see how he can herd the 60 cats. And not even LBJ, if resurrected today, could twist arms the way he did back in the Great Society heyday of 1965. Johnson cut deals with recalcitrant Democratic senators by putting pork projects in their districts, but those "earmarks" are politically verboten today.

The bottom line is that Democrats are notoriously prone to indiscipline - unlike the Republicans, by the way. George W. Bush reached the White House after having lost the popular vote, and he only had 50 senators on side; nevertheless, he and they governed in lockstep, acting as if he'd won a conservative mandate in 2000, and wound up enacting several major tax cuts. Republicans are simply better at taking direction from the top; by contrast, the last collaboration between a super-majority Democratic Senate and a Democratic president (Jimmy Carter) was a disaster.

Franken's arrival is already emboldening the Democrats' liberal wing. In an interview with The Huffington Post, Vermont Sen. Bernie Sanders has thrown down the gauntlet, demanding that all 60 senators stand together now and pledge in advance to break any GOP effort to filibuster a health care reform bill that contains a public option.

He said: "I think that with Al Franken coming on board...the strategy should be that every Democrat, no matter whether or not they ultimately end up voting for the final bill, is to say 'we are going to vote together to stop a Republican filibuster.' And if (an anti-filibuster Democrat) ends up saying, 'I'm not gonna vote for this bill, it's too radical, blah, blah, blah,' that's fine. I think the idea of going to conservative Republicans, who are essentially representing the insurance companies and the drug companies, and watering down this bill substantially, rather than demanding we get 60 votes to stop the filibuster, I think that is a very wrong political strategy."

The stakes have gone up, expectations have been raised, and the Democratic base will be less tolerant of failure. The arrival of the Senate's first career humorist has actually lowered the prospects for comic relief.