Sarah Palin has always been something of an unquantifiable entity in US politics. Partly that’s a result of her newness: I often forget that we’ve only really known of her for 18 months, since John McCain picked her as his running mate. In a short time she’s become one of the leading figures in US politics; perhaps the most important conservative in America.

In a sense, it’s no surprise she’s achieved this status. Aside from her novelty as a young, electorally-successful Republican woman, the appeal of Sarah Palin lies in her relatively ‘pure’ version of conservatism, which, in emphasising tax cuts, limited government, and social conservatism, appeals strongly to the less moderate elements of the American right. And Palin’s main narrative — that she’s an insurgent against the ‘liberal’ mainstream media and political culture — surely resonates with many who feel disenfranchised, who honestly believe the political process does not stand for them. She is not a popular candidate for nothing; people are swayed by what she is and stands for.

But Palin has made — and continues to make — significant strategic errors. We know all the old ones: the Katie Couric interview, the attack on Levi Johnson, her resignation as Alaska Governor (“I am not a quitter”). The excuse for all this was always that Palin is, as a political strategist, totally inept. A lot of candidates are, which is why they hire professional strategists. Relatively recently, Palin has. But they’re doing a pretty average job. Or rather, they’re only doing a good job within very narrow bands, and failing in all other senses.

Let me explain. First, Palin’s approach seems always to go on the attack. She’s good at that, so in some sense it’s a sensible strategy. But she’s not very good at targeting her attacks tightly enough, and it tends to make her look hyper-partisan, kneejerk, and uncontemplative — she looks and sounds like an opportunist. See this week’s latest back-and-forth: Rahm Emanuel should resign for saying “retarded”, but Rush Limbaugh should not even be criticised for saying the same thing; here Palin comes off as a cheap hack. Second, she’s undermined a key part of her appeal — her outsider status — by taking the corporate buck in the shape of a Fox News contract. This makes her less credible as an independent, insurgent force, even if Fox News is the least ‘mainstream’ of the US channels. Third — and most importantly — she’s becoming too connected to the more radical right. This hurts her not just among moderate Democrats and independents, but also among most Republicans.

Palin’s latest big strategic move is to align herself with the Tea Party movement. The movement is best described as organised anger. The Tea Partiers are, at their core, anti-tax pro-small-government protesters. But their opinions also frequently extend into the bizarre memes of right-wing extremism — my personal favourite being that the economic crisis was an event precipitated by Democrats to enable them to turn the US into a socialist paradise. These are Glenn Beck’s guys. Most Americans genuinely don’t find the movement appealing, and the many that do probably already were with Palin. Moderate Republicans think of it as the black sheep of their family, and the source of many of the party’s divisions. But this week it became pretty clear that Palin is keen to become the de facto head of the movement — she headlined their convention at the weekend, and has offered support to several tea party-supported ‘conservative party’ candidates running against moderate Republicans.

This strategy is bad for Palin, because whilst she can win the Republican primary in 2012 as the Tea Party candidate, she can’t then win the general — she’s doing a good job of hardening her base (and that’s important), but she’s doing a spectacularly bad job at reaching outside her comfort zone; this is a poor electoral strategy, because you need significantly more than the base to win.

It’s bad for Republicans, because if she puts her weight behind the Tea Party, the Republican Party will be pulled to the right in the midterms by the serious threat of conservative challenges against moderate Republicans in primaries and general elections (just as in NY-22 House race last year). This will make the party less electable in the long-term, and in the short term gives the Democrats the opportunity to play merry hell (even with their current difficulties) in the face of a divided opposition.

And it’s bad for the country. A more polarized Republican Party means a more polarized Congress. American government is inefficient right now. Compromise is near impossible at the moment, even with the presence of moderate Republican elements. Try and get anything done when those moderates are gone.