Joe Perez, a Democratic party activist and Obama devotee, is involved in a different midterm election to the one you may have been reading about. In his own state of Colorado, Democrats risk losing three house seats and one senate seat. But while pundits refer to an "enthusiasm gap" and reporters chronicle liberal disillusionment, Joe encounters a receptive audience. He believes that once people realise what's at stake and what has been achieved their interest and engagement will be restored. As he told me:

"When they are educated on the candidates, their enthusiasm resurfaces. I'm not hearing disappointment. There're some people who understand that progress has not been made but it has been blocked by the party of 'No' [Republicans]."

With less than two weeks before the elections, Perez may be engaged in wishful, but not entirely delusional, thinking. The long-predicted suggestion of a Republican rout of the Democrats is certainly the most likely result, with most pollsters betting on a 50-seat gain in the house and around eight seats in the senate. But it is by no means assured. Recently, if anything the big picture has become less, rather than more, clear – due to two countervailing trends.

The first is that many Democratic strongholds that once appeared safe are now vulnerable. The second is that some places where the Republicans once had a decisive edge are now tightening in the Democrats favour. The combined upshot of those two developments is a growing number of marginal seats that neither side can bank on.

Where the senate is concerned, Colorado, Nevada, West Virginia, Illinois – where Republicans have held narrow leads – the difference between the candidates remains within the margin of error.

To that, one can now add Pennsylvania and Kentucky, where Democrats are mounting a slight comeback, and Alaska where a third-party candidate – Lisa Murkowski, who was ousted by Joe Miller, a Tea Party supporter in the Republican primaries – is now neck-and-neck with Miller. Simultaneously, on the west coast, two states Democrats hoped were safe – Washington and California – are now up for grabs.

The contests for the house of representatives are even more tricky to predict because relatively few non-partisan polls are conducted and local factors can make national generalisations unreliable.

At this stage, the difference between victory and defeat will come down to the "ground game": the relative efficiency of both parties to identify their bases and get them to the polls. This does not completely alter the likelihood of Republicans taking the house or Democrats clinging on to the senate. But what it does change is the confidence with which any predictions can be made about the extent of Democratic losses and the possibility of even greater volatility between now and election day.

"For the time being, we are still in a universe where Democrats could probably hold the house by having the coin come up heads in a sufficient number of tossup races," writes Nate Silver in his New York Times blog.

The Democrats have the greatest challenge in translating support into votes but, by most accounts, they also have the most effective get-out-the-vote operation thanks to some of the apparatus still in place from 2008. That is why Obama and Biden have been stumping so hard and will continue to do so right down to the wire.

The Republicans, on the other hand, already have a motivated base. Their greatest challenge is to stop making the kind of gratuitous gaffes that might do more to energise Democrats than anything Obama could say. In large parts of the country, there is still much to play for. But Democrats are not playing to win – just not to lose too badly.

The author of this piece, Gary Younge, has been participating in the conversation below as GaryYounge. This is an excerpt selected by a Cif editor:

criticalthinkerrrr says:

The races that the Democrats are going to lose, are the ones they won last time in solidly red districts, and the Tea Party folk and Republican candidates will still lose in the solidly blue districts. In a way I actually hope Tea Party folk and Republican candidates win, because by 2012 people will remember why they voted those "do nothing" types out in 2008!

wynper follows up:

I am with criticalthinkerr on this one. How short people's memories are! Eight ghastly years of Bush with all the muddled thinking, inefficient agencies (heck of a job, Brownie), illegal wars, torture, deregulation, tax cuts for the very rich, Cheney's paranoia, and finally economic catastrophe and bank bailouts. And yet, Americans seem ready to hand the shovel back to those who dug the hole.

GaryYounge replies:

@ wynper, critical thinkerr: the problem with the notion that if the Republicans win people will remember how bad they were in 2008 is precisely that people's memories are sufficiently short that they by 2009 they forgot who was at the helm when the Obama took over, who was in charge when the banks were bailed out and who ran up the deficit. The tea party rally I was at last night, headed by Gingrich in Vegas, they blamed Reid and Obama for the housing crisis. The most popular placard was calling for Jobs. There is an artful populist veneer to the tea party movement that relies on poor memory. There's no reason to think that by 2012 people's memories will have improved any.