Both the Obama Democrats and the McCain-Palin Republicans had, by any measure, very successful political conventions.

Both achieved what the modern convention exists to do: They unified their bases and pivoted toward the sprint to election day.

Obama had his odd Greek columns/rock concert setting of some 85,000 people crammed into a sports stadium for his speech. But Alaska Gov. Sarah Palin, whose speech drew nearly as many television viewers, clearly changed everything about the fall campaign. Obama is no longer a presumed front-runner, and he and running mate Joe Biden will have to earn the front-runner mantle.

The person and the speech everyone is talking about is not Obama. The buzz is all about Sarah Palin, who not only demonstrated in her speech that she is in fact ready to campaign nationally, but also, critically, breathed life into a GOP base dispirited by a barely competent White House and a Congress that lost its way.

The most common description of the Palin pick and her performance, after her speech: Home run. Indeed, there has not been such a memorable convention moment in a generation.

Early polls show the presidential contest has tightened considerably, and the candidates are effectively tied. That's good for the country, for it means that the coming weeks will have to focus on the very real differences between the candidates - on the substance of issues, on character, and, yes, on style. But not style in its shallowest sense. Style in the sense of how the respective candidates would approach the office.

On that count, Obama and McCain moved in opposite directions. Obama, in picking Biden as his running mate, cleaved himself to conventional Democratic partisanship, complete with fealty to its major factions. McCain, in sharp contrast, even more clearly identified himself and his campaign as being about reform and not being of and for Washington. In his acceptance speech, McCain pledged to make real changes in the federal government.

So now the race is on, with contrasting candidates and campaigns. Whoever wins will have to earn the victory - and that is as it should be.