The whole world is watching.  (Or at least political nerds are watching.)

With Democratic senate seats predicted to flip over to Republicans in Pennsylvania, Indiana, Illinois, Wisconsin, Arkansas, North Dakota, Colorado, and Nevada tonight, bringing the GOP total to 49 seats—all eyes fall on Washington at 8 pm our time. In fact, all eyes fall on King County.

There are 3.6 million registered voters in Washington State. The Secretary of State is predicting a record off-year turnout, 66 percent—or 2.4 million ballots cast. And 60 percent of those will be posted and counted tonight shortly after 8 pm.

Shouldn't 60 percent be enough of a sample to see if U.S. Sen. Patty Murray holds the line for Democrats at 51 seats or if Republican challenger Dino Rossi gives the Republicans 50? (At a 50/50 split, watch for Independent Connecticut Sen. Joe Lieberman or conservative Nebraska Democrat Ben Nelson to saunter over and caucus with the GOP).

It could be enough. But it depends on what the results in King County look like.

King County is the most populous county in the state, with 1.1 million registered voters (about 30 percent of the state's vote). We're only going to see about 40 percent counted from King County tonight, about 350,000. That leaves another 370,000.

King County is expecting a fat 68 percent turnout overall, or about 720,000 ballots cast. (In the last off-year election, 2006, King County had a 65 percent turnout.) As of this morning, King County Elections has already received 409,000 ballots. They expect another 150,000 to pour in today (ballots mailed Monday) and another 150,000 to pour in on Wednesday (ballots mailed today). The remaining 10,000 or so will trickle in after that. So, we'll be in a bit of suspended animation tonight.

Here's how to read it: If Rossi is ahead by more than three points statewide, he's likely to win the whole thing. And he'll definitely be ahead. Not only does Rossi poll better than Murray in the rest of the state, but we're looking at earlier ballots—and Republicans will be overrepresented in earlier voting thanks to this year's "enthusiasm gap."  If he's only ahead by two or three points, though, Murray's showing in King County becomes the deciding turn in the national drama.

For the Democrats to retain control of the U.S. Senate, Murray needs to win big in King—north of 58 percent if Rossi is up two or three statewide. And here's where the enthusiasm gap comes into play in King County.

The predicted record 66 percent turnout statewide is riding largely on Republican voters. Just read between the lines of what Washington Secretary of State Sam Reed said when he predicted the massive statewide turnout: “Hotly contested races and ballots measures, heavy television spending, and fired-up grassroots activists all combine to suggest a strong turnout.”

That "fired-up grassroots activist" thing he's talking about basically means people who are pissed off at the current administration. And as we've said before, the ballot measures to repeal taxes, reinstate Tim Eyman's two-thirds majority rule to pass tax increases, privatize workers' comp, and privatize liquor excite Republican voters more than Democratic voters.

(Liquor privatization doesn't exactly break down along party lines because a solid core of urban progressives liking the idea. But on balance, with unions organizing suburban evangelical conservatives to come out against it and Democrats not 100 percent jazzed on this year's one progressive measure, the high-earners' income tax, the parade of initiatives help conservatives. Where was that anti-gay rights measure this year when Democrats needed it?)

For the Democratic vote to match Republican enthusiasm, it comes down to King County where, in 2008, Barack Obama won by 70 percent. (That was with 84 percent turnout, or 930,000 ballots cast.)

Turnout is not going to be that big this year, and even with the record off-year turnout, it's not clear who the Obama voters vote for. "They're just as pissy," a political consultant pointed out to Fizz. "If they turn out. Who do they turn out for?"

That sounds like a dumb question. You'd expect them to vote for Murray. And the Fizz does expect them to vote for Murray. Obama did, after all, come out and stump for Murray at a gargantuan rally at the U.W. two weeks ago. But how overwhelmingly will they vote for Murray? Here's the worrisome footnote for the incumbent Democratic senator: We're talking about independent King County voters who were drawn into the political equation in 2008 with a call for change. Now that they're here, they may very well be disappointed. For example, on the bellwether Eastisde, where Democrats currently control the state senate, internal Democratic polling shows incumbent Dem state Sens. Claudia Kauffman, Eric Oemig, and Randy Gordon going down. And a fourth, Rodney Tom, may also be in trouble.

When it comes to who controls the U.S. Senate, there are some big "Ifs" in Democratic King County: If King County voters turnout big and If they vote the party line.

There are some other big counties too, by the way. Pierce and Snohomish. Sen. Murray needs to be hovering slightly above Dino Rossi, by about one or two points, for all the rest of this fragile Democratic equation to hold.

King County ballot drop locations here.