The selection of Paul Ryan as the Republican vice presidential candidate remains a curious one.
He brings no foreign policy experience to the ticket - normally considered a must if the top name has little. He doesn't come from a crucial swing state that may be important in the final equation (remember Florida?). And, most crucially, his views on government welfare programmes, his socially conservative position on issues like abortion and same-sex marriage are unlikely to attract large numbers of independents.
The convential wisdom is that US politics is now so polarised - each side fears the other will do their absolute worst if elected - that many people have already decided how they'll vote.
This, it is believed, leaves a small group of independents in each swing state up for grabs. And so a lot of money - and we're talking tens if not hundreds of millions of dollars - will be spent between now and November 6 trying to convince a few thousand voters who can make the difference.
Before the independents come into play, though, each party must ensure it turns out its core support. That is much more important for Mitt Romney. He won many primary contests in a less than convincing fashion. For so long it appeared the Republican party was looking, hoping, for someone else to emerge to seek the nomination. That may explain why there were so many frontrunners through the long primary process. It was as if the party was looking for anybody but Mitt.
Many Republicans have never been convinced Mitt Romney is one of them. They remember how he ran for the senate in Massachussets as a moderate Republican, how his liberal views on abortion have "evolved" to the firm conservative views he holds now how he even admits voting for a Democrat in a primary election.
And so the selection of Paul Ryan is a nod to the doubters, a move to motivate supporters, to give them something more than their antipathy towards President Barack Obama to go to the polls
Steve Benen, a liberal commentator suggests there are three types of vice-presidential picks. There's the one you select to help you govern if elected: the January choice. Then there is the candidate you select to help you win an election: a November choice. Finally, there is the August pick: someone who will help you unite the party, and satisfy the base if you aren’t strong enough pull them all together on your own.
Get enough of your own base out and you may negate the need to persuade independents. In 2004 - at the height of the Iraq war, with fairly unimpressive approval ratings George W. Bush and Karl Rove, his main strategist, virtually ignored the independents who had carried him to victory over Al Gore four years earlier. Instead, they concentrated everything on reminding Republicans that not only was America under attack, their President and their party was too. Republicans are generally regarded as much more enthusiastic. And so it was a winning strategy.
Romney's campaign hasn't yet given up on the independents or the apparently small number of undecideds. Neither has Barack Obama. Both camps are rallying their friends while trying to woo the middle. But if this becomes a battle of core supporters, Romney opting for Paul Ryan could well be the smartest decision of his sometimes troubled campaign.