The United States is notorious for the length of its election campaigns.

The next presidential election is still 20 months off, but that’s by no means too early for candidates to be shaping up. This time four years ago, most of the front-runners had already announced their candidacy and were busily organising and fundraising.

So if anything it represented a somewhat late state when Newt Gingrich last week announced the formation of a fundraising committee, thereby becoming the first major semi-declared candidate in the Republican field.

The big difference of course from the last election is that there is an incumbent president running. That means that the only real primary contest will be among the Republicans (the chance of Barack Obama facing a Democrat challenger is remote), and also that some Republicans may choose to sit out this cycle in the hope of an easier target in 2016.

Gingrich, however, a former speaker of the house of representatives and most famous as the face of the “Republican revolution” of the mid-1990s, will be 69 when the election rolls around and has already backed away from candidacy once, after having put his toe in the water in 2007. It’s pretty much now or never for him.

There are three other high-profile Republicans who are widely assumed to be planning a run: Mitt Romney and Mike Huckabee, who both ran in the primaries in 2008, and Sarah Palin, who became the party’s vice-presidential candidate.

Behind them is a long list of possible names: Mitch Daniels, Tim Pawlenty, Haley Barbour, Jon Huntsman, Ron Paul, Chris Christie, Gary Johnson and many others. But they will start (if they run) well behind in terms of name recognition or fundraising ability. Only Pawlenty, a former governor of Minnesota who was passed over in favor of Palin as John McCain’s running mate, looks as if he might be able to match it with the big four.

Gingrich’s place in this field is somewhat anomalous. He has never run a national campaign, and never been either a senator or governor. He is certainly well-known, but not particularly well-liked, and even among Republicans his rather colourful background — including his three marriages, his role in the 1995 budget crisis and his often unconventional policy ideas — will give him problems.

Nate Silver, assessing his chances last week, pointed out that Gingrich’s approval ratings are behind the other three front-runners when it comes to Republican voters, and ahead of only Palin among voters in general. As he puts it, Gingrich “is perhaps one gaffe away from joining her on the other side of the 50% unfavourable mark”.

Romney and Pawlenty appeal to the more centrist vote, and even Huckabee, a hard-line evangelist, has more moderate appeal due to his folksy style and populist economic policies. Gingrich and Palin, however, will be competing for much the same sort of Republican voters, the “Tea Partiers” and others on the radical fringe.

While Gingrich is an incomparably more serious intellectual and policy thinker than Palin, policy depth is not really what those voters are looking for. His attempts so far to pander to the extremist vote have seemed clumsy, alienating moderates without getting much compensating gain.

Gingrich’s best hope at the nomination is probably if Palin declines to run and he can stand out as the most extreme of the serious candidates.

But in that case it’s hard to see how he could put together a winning campaign against Obama.