Although many in the media have acted as if the presidential contest were competitive, it’s been apparent for weeks that Sen. Barack Obama (D-Ill.) has been headed for a clear win.

[IMGCAP(1)]Call it a wave or a blood bath, as I did in this space almost a month ago, on Oct. 7 (“For Republicans, Another Blood Bath Looms on Horizon”), the combination of a strong anti-Republican mood, news events that fueled the public’s strong desire for change, and the Democrats’ huge financial and organizational advantage this cycle also guaranteed big Democratic House and Senate gains.

The presidential race has been a foregone conclusion since shortly after the nation’s financial crisis exploded in the news a little more than a month ago. The virtual elimination of national security as a top issue, combined with Obama’s coolness in the face of the public’s near hysteria, helped him close a deal that he previously had not closed.

Polling for the past few weeks has shown voters increasingly comfortable with the Illinois Democrat, giving him better and better reviews on a number of issues and characteristics. His favorability rating (56 percent positive/35 percent negative) in the Nov. 1-2 NBC News/Wall Street Journal poll is better than Sen. John McCain’s (R-Ariz.), and the two men are even on the question of who “has a background and a set of values that you can identify with” — down from a 10-point McCain advantage in August and a 6-point McCain advantage in the Sept. 19-22 poll.

Even more important, now a majority of whites, 51 percent, say Obama has the background and values with which they can identify. Reputable national polls have shown Obama lengthening his lead, and the polls’ internals show why that is happening.

While it certainly is true that this isn’t a national presidential election as much as it is 50 state elections, it’s unwise to ignore the national numbers and focus on much less reliable state polls, some of which allegedly show the race closing. Obama already appears to be over the 270 electoral vote mark, and if that’s the case, it doesn’t really matter if he wins Ohio or North Carolina.

The fights for the House and Senate were over well before the presidential contest was decided. We’ve known for months that this would be a good Democratic year. All that remained to be decided was exactly how good a Democrat year it would be.

Democratic gains of seven or eight Senate seats, with a decent shot at nine, have appeared likely for weeks, and that’s still where Democrats are. Senate races in Virginia, New Mexico, Colorado and New Hampshire have been over for months. Democratic challengers appear to have a distinct advantage in Alaska, North Carolina and Oregon.

A mini-comeback by Sen. Norm Coleman (R-Minn.) has all but erased the small but consistent advantage that Al Franken (D) has had for a few weeks, now making that state’s Senate race a pure tossup.

Obviously, to reach the psychologically important 60-seat mark Democrats will need to win two out of four competitive races: Minnesota, Mississippi, Kentucky and Georgia, a tall order given the Southern states’ political dynamics. But it isn’t impossible, especially in a wave election.

It’s certainly possible that we will all wake up Wednesday morning with Democrats gaining eight seats and Georgia headed for an early December runoff, with the outcome there determining whether Senate Majority Leader Harry Reid (Nev.) will have 60 seats or 59 seats (or 58, depending what Senate Democrats do about Connecticut Independent Democratic Sen. Joe Lieberman).

In the fight for the House, anything from a Democratic gain in the mid-20s to a much bigger Democratic net gain of around 40 seems possible, with gains in the 27-33 seat range most likely.

Anyone wanting to chart the night might pay special attention to three groups of races.

First, there are the purest of tossups. If one party wins most of them, that will say something important about the overall results of the elections. Those districts include half a dozen Republican seats: open seats in Kentucky’s 2nd district, Maryland’s 1st, and New Jersey’s 7th, and re-election contests involving Rep. Steve Chabot (Ohio’s 1st), Thelma Drake (Virginia’s 2nd) and Dave Reichert (Washington’s 8th).

Second are a number of Republican seats that are tossups but that seem to favor Democrats ever so slightly, particularly in a wave election. If Republicans hold on to many of these districts, the night may not be as good for Democrats as many assume. These include three open seats — Minnesota’s 3rd district, New Jersey’s 3rd and Ohio’s 15th, along with the re-election bids of Reps. Michele Bachmann (Minnesota’s 6th), Christopher Shays (Connecticut’s 4th) and Jon Porter (Nevada’s 3rd).

Finally, there are GOP seats where the Republican has anything from a slight edge to a much more considerable advantage. If many of these seats fall to Democrats, Republicans could well lose 40 seats. These districts include Ohio’s 2nd (Rep. Jean Schmidt), South Carolina’s 1st (Rep. Henry Brown), Virginia’s 5th (Rep. Virgil Goode), Indiana’s 3rd (Rep. Mark Souder), California’s 3rd (Rep. Dan Lungren), and the open seat being vacated by Rep. Barbara Cubin (Wyo.).

Wave elections normally sweep in a number of candidates who, under normal circumstances, would not win in their own right. That’s likely to happen this year, especially given the Democrats’ financial advantage. A remarkable turnout for Obama could also benefit Democrats downballot.

If you are looking for upsets that few others are paying any attention to, be sure to keep an eye on the Louisiana Senate race, a couple of Texas House races (7th and 10th districts), Democratic Rep. John Murtha’s race, and the open seat in California’s 4th.

Finally, turnout (on both sides) remains a huge factor. Most observers and many pollsters have been expecting a spike in younger voters, African-Americans and first-time voters nationally. Whether that happens, and how big a spike that might be, will affect the bottom line today.

Stuart Rothenberg is editor of the Rothenberg Political Report.