Every presidential election is different. Rules-of-thumb about election winners and losers -- "no president has ever been reelected with an unemployment rate as high as Obama has," (often repeated in conservative circles, but not true) -- rarely survive scrutiny. And bromides about the presidential nominating process don't stand up any better: a drawn-out nominating process doesn't necessarily doom a party (see: Democrats in 2008) nor does a quick walk to the nomination (see: Al Gore in 2000) assure victory in November. But Republicans who think that this year's long nominating process will help the party the same way that the 2008 process did for the Democrats are wrong. It's not because there's something about nominating processes themselves but, rather, the things that made the 2008 nominating process a net positive for Democrats do not apply to Republicans in 2012.
The candidates themselves should come first. Both late stage 2008 Democratic Party candidates were, by any measure, exciting. The Democrats, early on in the process, decided that they would make history by nominating either a woman or an African-American to head the ticket. Both Barack Obama and Hilary Clinton, at their best, compelling public speakers and terrific debaters. Nominal frontrunner Romney is, at best, a passable public speaker. Santorum does better on the stump but may have the worst case of foot-in-mouth disease of any national political figure of the TV era. Although Santorum does have working class roots, furthermore, both are rich white guys typical of the Republican Party stereotype.
The ability of either potential nominee to truly unite the party is also in question. In 2008, both Obama and Clinton were, broadly, acceptable to all key Democratic Party coalitions: both had records of voting in lockstep with labor union leaders, were quite popular among African-Americans (Clinton actually outpolled Obama with this key Democratic group early on), had good Hollywood ties, maintained strong relations with environmental groups, and supported programs that would increase the size and scope of government. Romney and Santorum, on the other hand, both have serious weaknesses with key Republican groups. Romney's previous pro-abortion, sometime secularist stances (and, perhaps, his own Mormon faith) have delivered him defeat after defeat with evangelical voters. On the other hand, Santorum's previous opposition to free trade agreements, half-baked tax plan, often obnoxious way of conveying social conservative messages, and sometime support for big spending make him unacceptable to business and libertarian factions of the GOP. Party unity, of course, will eventually come but it may end up being awfully grudging.
Finally, while the Great Recession's beginnings coupled with troubled war efforts gave Democrats an obvious way to pummel the GOP nominee in the 2008 cycle, today's Republican Party doesn't have the luxury of having events create the campaign message for it. Although some broad themes -- growth of the debt, still lackluster economy, likelihood of big tax hikes in a second Obama term -- suggest themselves, they don't add up to a convincing case to unseat Obama. Creating a compelling message as well as workable alternatives to Obama's policies will take time and, the longer the nominating process drags on, the less of that the eventual nominee will have. Given that both still viable candidates seem likely to advance distinctly different general election messages, furthermore, a long nominating process will drain them of the time they need to get their general election messages out.
The bottom line is not good for the GOP. Every day that the nominating process goes on is another day that Republicans snipe at one another and allow President Obama the continued luxury of the Presidential bully pulpit. If Republicans want to have any chance of winning, party elders need to do their role, get Rick Santorum and Newt Gingrich to drop out of the race, and rally around the one candidate, Mitt Romney, who could still win in November.