It's already become fashionable on the left to poke fun at the Republicans' presidential prospects in 2012. The Guardian's Richard Adams, referring to the current GOP crop, calls them "a cast of has-beens, nobodies and deadbeats." Former Arkansas Governor Mike Huckabee, the presumptive GOP frontrunner, warns of a potential "bloodbath" and candidly admits to being deeply pessimistic about beating Obama. That's why, despite his strong polling lead in Iowa, a potential stepping stone to the GOP nomination, he's probably not going to run.

But here's the irony: the big political battleground in 2012 may not turn out to be the presidency, but the Senate.

Twenty-three Democratic Senate seats are up, compared to 10 GOP seats – less than half as many. And with Democrats currently holding a 53-47 majority, just four seats need to switch hands for Republicans to regain the majority, and to recapture full control of Congress. Long-time political experts like Charlie Cook, author of the highly influential "Cook Report", likes the GOP's chances – a lot.

And what will that mean? Every level of government, the Congress, the bulk of the statehouses (the governorships) and most of the state legislatures – both their lower and upper chambers – will be in Republican hands. Except for the presidency, of course. But what kind of presidency will it be if it's a Democratic island surrounded by a conservative sea? Republicans have so boxed Obama in politically – on the budget and healthcare reform, and just about everything else, it seems – it's not clear they even need the presidency; at least, not yet.

In fact, without control of Congress, Obama won't be able to do much – except veto Republican legislation. While vetoes are difficult to override, and can be useful as a political lever, a president who rules by veto alone isn't really governing anymore. At a time when the country wants genuine legislative action, he can even start to look "obstructionist".

Here's an alternative "theory" about 2012 that's starting to gain currency: the GOP, realising that its "brand" is still badly tarnished, and armed with a bevy of new, more attractive political candidates still too "green" to run for president in 2012, is basically sitting this one out. They don't want to take power prematurely and get stuck managing the US economy, which, while improving marginally, is certain to languish for some time. Why not leave a lame-duck, neutralised Obama in place to take the blame, while patiently laying the groundwork for 2016?

In fact, by all appearances, the Karl Rove wing of the GOP, has all but folded its tent. Its favourite "comer", Senator John Thune, quietly withdrew two months ago, shortly after another conservative favorite, Representative Michael Pence, announced he wouldn't run, either. And the two biggest GOP moderates, former Florida Governor Jeb Bush and Indiana Governor Mitch Daniels, are almost certainly out, too. Bush, and New Jersey Governor Chris Christie – conservative stalwarts, but independent-friendly to boot – are considered eminently electable,; both are young and have great political futures, especially Christie.

But neither is anxious to be his party's sacrificial lamb in a second-term presidential battle that typically favours the incumbent.

How good, then, are the GOP's chances in the Senate?

In 2010, Republicans picked up six seats, which, along with their historic conquest of 63 House seats. That destroyed the Democratic super-majority, and dashed any hope for a progressive realignment of US politics. And two recent Gallup polls confirm just how vulnerable the Democrats still are. In 2008, 30 states became "solidly" Democrat, compared to just four for Republicans. Few states have suddenly gone solidly Republican since then, but now 16 of those solidly 30 Democratic states are deemed either "competitive" or "lean Republican".

They include Florida and Virginia, two key bellwether states Obama won in 2008, as well as most of the south-western "swing" states. Voters in these states just elected Republicans at all levels. It's a potential sea-change in the making, and it makes Obama's re-election – notwithstanding his likely advantage in Wisconsin, Ohio and other states galvanised by GOP union-busting – increasingly precarious.

The danger signs are also apparent in a separate Gallup poll that shows the favorability rating of Democrats falling below 50% for the first time in two decades. Both parties share similarly low favourability ratings – roughly 43% each – but until recently, the Democrats had averaged 53%, compared to 46% for the Republicans. In fact, the Democratic approval ratio is down to its lowest level since 1992, the year that Bill Clinton took power. The GOP's ratio is back to its 2005 level. That means that, for most of the electorate, the "stain" of the second Bush presidency – a key factor in the Democratic surge in 2006-2008 – appears to be gone.

Of course, that doesn't mean Republicans have suddenly won over large numbers of Americans; they haven't. But now it's the Democratic "brand" that's badly tarnished, eliminating the party's moral edge, especially among independents. And since House and especially Senate races – more than the president's own re-election bid – are profoundly partisan battles, the GOP's improved rating relative to the Democrats' could prove decisive, indeed. Only more so if the GOP decides to leverage its resources for an eminently winnable battle for the Senate, rather than trying to take down a still-powerful incumbent president with the largest financial war chest and media outreach machine in US history.

More gaffes by the surging Tea Party diva Representative Michelle Bachmann, and the prospect of a political mudwrestling contest with her fast-fading pal Sarah Palin could make for amusing comedy. Toss in a drawling Southerner, Haley Barbour, the windy Newt Gingrich, and yes, come June, "The Donald" and his antics, things could get positively buffoonish out there. But laugh all you want, because in the states, the most important 2012 battleground, the consolidation of conservative power may be all too apparent.

And here's more potential bad news: in 2014, another 20 Senate Democrats are up for re-election, compared to just 14 Republicans. That means over two successive election cycles, 43 Democrats – 80% of those currently in office - must defend their Senate seats, compared to just 24 Republicans. Could the GOP end up with a 60-vote super-majority of its own, just two years before laying siege to the White House in a post Obama contest?

It's a daunting prospect, and presidential follies aside, no laughing matter.