The conventional wisdom in politics is that the best way to ensure victory in a general election is to avoid a bloody primary.  I'm not sold on this particular bill of goods.

It goes without saying that an incumbent is always weakened by a primary challenge.  However, I believe that is less because they are weakened by the challenge than because their weakness invited the challenge in the first place.  In other words, an incumbent who is vulnerable to an intraparty fight for the nomination is less likely to win re-election to begin with.

In a wide open field of candidates, however, an easy primary fight usually results in the coronation of a candidate whose response mechanisms and perseverance are untested.  The result is typically that the campaign is caught flat-footed when the opposition hits them with the customary mud-slinging that has become the hallmark of political life in America.  A couple of recent examples:

1992:  Then-Governor Bill Clinton had to survive a Democratic Party nominating process that more closely resembled a minefield than a primary election.  He had to come back from the Gennifer Flowers scandal and the alleged 'draft-dodging' scandal just to finish second in New Hampshire.  A strong Super Tuesday showing seemed to wrap up the nomination for Clinton, but surprise victories in the northeast by former California Governor Jerry Brown extended the nominating process well beyond any date that pundits and politicos thought safe for a candidate for President.  But the George H.W. Bush campaign learned that fall just how tough Clinton and his team had become, as they counterpunched their way to electoral victory.

2000:  Vice-President Al Gore got a scare from Senator Bill Bradley, but he recovered in time for the primaries, sweeping to victory without losing a single state.  On the Republican side, Texas Governor George W. Bush fought Senator John McCain tooth-and-nail for the GOP nomination.  Bush won Iowa; McCain won New Hampshire; Bush won South Carolina; McCain won Michigan.  And on it went, until consecutive Super Tuesday contests sealed the victory for Bush, who went on to win the Presidency against the heavily favored Democratic standard-bearer, Al Gore.

2004:  Senator John Kerry's surprise win in Iowa slingshotted him to the nomination, as his momentum propelled him from victory to victory.  Senator John Edwards and General Wesley Clark each won a state, but these were exceptions, not the rule.  Kerry glided to victory after Iowa, only to face a bare-knuckled Bush-Cheney campaign in the fall and to be caught seemingly unawares by the "Swift-Boat Vets for Truth".  His campaign's sluggish response to these attacks resulted in the whittling away of what had been a significant lead in the polls until Bush finally caught him and went into the lead to stay.

Make no mistake:  hard-fought primaries are costly affairs.  However, there is an upside.  Campaigns that face challenges are more likely to sharpen their operations and find their weaknesses sooner rather than later.  They develop a flexibility and agility that is invaluable in the full-contact world of politics.  Given the choice between a coronation and a contest, I'll take the contest every time.