Standing approximately 35 feet away from Senator Joe Lieberman as he delivered his speech at the Republican National Convention last night I turned around at one point to get a good look at the delegates seated in the hall. As I surveyed the crowd, I had an overriding thought: 'This place is really white.'

Now I know it's a bit of a cliché to suggest that Republican conventions are largely white affairs, but the contrast between the extraordinary diversity of Invesco Field and the veritable sameness of the demographic make-up at the Xcel Center in St. Paul is perhaps the most striking feature of the two conventions.

It would hardly seem surprising that at the nomination of America's first African-American candidate in Denver there would be a diverse crowd, but really it was more about the type of diversity. At Invesco, I was surrounded by blacks, Hispanics, Asian-Americans and whites; young and old; male and female; gays and straights were all represented. In just my one section, of an 84,000-person filled stadium it felt like the realization of the melting pot of America.

Absolutely the same cannot be said about the goings-on in St. Paul. The crowd consisted of middle-aged white men and middle-aged white women with some young people and a mere smattering of non-white Americans.

Apparently my eyes don't lie. At the DNC, 34 percent of the delegates were black or Hispanic. At the RNC, 93% of delegates are white, 5% Hispanic and only 1.5% African-American - in fact, it is the lowest black delegate representation at a Republican convention in 40 years.

Now on one level, being seen as the white party in American politics has paid enormous political dividends for Republicans over the years. Since 1964, Democrats have never won more than 50% of the white vote - and their conventions have always been more diverse affairs. In a majority white country it's a good reason why Republicans have won 7 of the last ten presidential elections.

But as that old troubador from 1964 reminds us, "the times they are-a-changing." According to the most recent census white non-Hispanics only make up two-thirds of the population and that number is shrinking. Amazingly, 45% of those under the age of 5 are not white. And by 2042, America will be a minority-majority country as whites will be less than 50% of the population.

According to William Frey, a Brookings Institution demographer, "The white population is older and very much centered around the aging baby boomers who are well past their high fertility years. . . The future of America is epitomized by the young people today. They are basically the melting pot we are going to see in the future."

Indeed the demographic difference between the nominees, an older white male and a young African-American, is being reflected in the two candidate's key supporters. Barack Obama is capturing 90% of the African-American vote; he is outperforming 2004 Democratic nominee John Kerry among Hispanics and he is cleaning up with young voters. In short, his support comes from the part of the population that is fastest growing. John McCain's support comes largely from white voters and in particular older Americans. At a time when the Republican brand is clearly in decline, the party must find a way to reach out to more diverse and younger voters. Instead they are relying, for this election, on a declining segment of the population. Quite simply, this is a long-term recipe for political disaster for the GOP.

Now some would argue that Sarah Palin is the type of Vice Presidential pick that could improve the party's appeal to younger voters. But this is sort of like assuming that simply because she is a woman, female voters will flock to her candidacy. In reality, Ms. Palin is a conservative at a time when the country appears to be getting more liberal; and is a religious conservative at a time when the electorate, particularly younger voters, are showing less religious affinity. In fact, those under 30 are the most secular group of Americans.

Of course, this is not to say that John McCain will necessarily lose the 2008 election. America is still a majority white country and with an African-American atop the Democratic ticket we are in unchartered political territory. But having stood on the floor of both convention halls this past week, it seems quite clear that Denver represents the future of American politics - and St. Paul is the past.