Let the right one in: Republicans contesting the nomination for the 2016 US election are impressive in both number and quality

In the land of the permanent campaign, one election may only just be over, but skirmishes for the next one have long since begun. Fresh from securing control of both houses of Congress in November’s midterms, the Republicans have their sights set on the most important prize of all, the White House – and the battle for the GOP nomination is shaping up as one of the most fascinating in decades.

At this early stage in proceedings, the contrast between the two US parties could not be starker. Despite some unhappiness on the populist left, the Democrats seem already to be coalescing behind Hillary Clinton, with no credible rival in sight. For the Republicans, however, there is no such sense of inevitability. At least two dozen potential candidates have expressed an interest in running, from seasoned state governors and ex-governors to old and new heroes of the party’s social conservative wing, not to mention a talented trio of first-term senators.

These are of course early days. The Iowa caucuses that kick off the 2016 primary season are still a year away. Nobody has yet formally thrown their hat into the ring, and polls are little more than measures of potential candidates’ name recognition, among voters who have yet to focus on the contest. But one crucial process is unfolding: the so-called “invisible primary” when aspiring entrants seek to line up donors for a nomination battle that alone will cost at least $100m (£66m). Money is the mother’s milk of American politics, and over the coming weeks various undeclared hopefuls will conclude that they have no chance of amassing the financial support to stage a credible campaign.

The Republican jostling reflects one overriding fact, that 2016 is an eminently winnable election. Only once in the past 60 years (George HW Bush in 1988) has the same party won a third election in succession – but in terms of public affection, Barack Obama is no Ronald Reagan, while even Ms Clinton is hardly the irresistible juggernaut she seemed a few months ago.

Meanwhile, the emerging Republican field is far stronger than its 2012 equivalent (readers will remember such luminaries as the pizza magnate Herman Cain, briefly the front-runner) which, in the person of Mitt Romney, threw up one of the most inept election candidates in recent memory. Mr Romney appears bent on running again, but outside hard-core loyalists, the feeling among Republicans seems to be that his time is past.

In any case, unlike 2012, the party has plenty of other options – above all a phalanx of past and present state governors, including Jeb Bush, who led the vital swing state Florida from 1999 to 2007, to New Jersey’s Chris Christie, Louisiana’s Bobby Jindal, and a couple of potentially formidable Midwestern governors, John Kasich of Ohio (another key swing state) and Scott Walker of Wisconsin.

At this early stage, the best bet is that the nominee will come from the category above. Of Mr Obama’s five immediate predecessors, four were governors. All had the benefit of being able to claim executive experience, while being untainted by “Washington”, an especially potent argument now, given the hyper-partisan dysfunction of the capital’s politics.

Americans moreover tend to choose a president of opposing characteristics to his predecessor: the slippery Bill Clinton was followed by perceived straight-arrow George W Bush, and inarticulate, shoot-from-the-hip Bush by the inspirational and cerebral Obama. All else being equal, it thus seems unlikely voters will go for another untested Senate first-termer like Ted Cruz of Texas, Marco Rubio of Florida, or Kentucky’s Rand Paul. But for whoever prevails, one truth is immutable. The next Republican nominee will, as always, be centre-right, not hard-right. Somehow though, they must navigate conservative primary electorates without lurching too far to the right. Otherwise, like Mitt Romney in 2012, they will be doomed.