With two of the three front runners in the Democratic pack not being a white male (Clinton & Obama), we are suddenly looking at the Democratic presidential nominee being either female or black. And this is not a longshot, a smart bet at the moment would be that one of these two will win.
What does this do to the Republican party? Well the polls show that being female and or non-white is now an advantage in the race. More people will vote for a candidate than will vote against them if they are not your standard white male.
So the Republican's have to plan assuming that running a pair of white males will be a significant disadvantage. Since their entire slate of presidential candidate is both white and male, that means to address this they must have a woman or non-white individual as the VP candidate.
And the Republicans have several well qualified candidates from Condi Rice to Mel Martinez. (Forget Colin Powell, I don't think he wants anything to do with the existing Republican party.) My guess is that over the next 6 months the Republican party will unofficially make a committment that the VP candidate will not be a white male.
So now we jump back to the Democratic primary. Assume for a moment that it is not Clinton or Obama (ie Gore or Edwards). But the Democrats now face a Republican slate that will have a woman and/or non-white VP on their slate. The Democrats cannot concede on this issue. At that point the Democratic VP must be a woman or non-white candidate. And it could in this case very well be Clinton or Obama.
And with the '08 election, it will be locked in. A slate of 2 white males will be a thing of the past. Neither party will risk the loss of votes. And it will stay "balanced" until this does not matter anymore.
Think balance on this is not a big issue? As far as I can tell, every single state has a "balanced" ticket for Governor/Lt. Governor. This country is already doing this at the state level.
And all I can say is - it's about time.