Since the 1970s, Iowa and New Hampshire have played pivotal roles in who becomes president of the United States. Winners (and even runners-up) in these early voting states have used their strong showings to gain much-needed media attention and win over new donors to fuel their candidacies in the months ahead. Both Barack Obama and George W. Bush used victory in Iowa as a trampoline to national success.

The presidential race is a marathon. But without victories early on, few candidates have had the resources to compete until the end. That's why so many candidates drop out after a poor showing in the Iowa caucuses, as both Joe Biden and Chris Dodd did in 2008. Without the springboard of an early-state success, long-term victory becomes all but hopeless.

That might be changing. Indeed, it looks like Iowa and New Hampshire might be supplanted this year. The new presidential power brokers? Fox News and, to a lesser extent, the other television networks.

With at least 14 Republicans officially running for president, and at least two more on the way, Fox News has a plan to limit participation in the first GOP debate, scheduled for August 6. Only the top 10 candidates in an average of the national polls will be allowed to participate. You could be a U.S. senator or governor of a major state, but if you don't make the cut you don't get a podium on the stage.

This winnowing of the GOP presidential field — which is normally handled by the Iowa caucuses and New Hampshire primary — is instead being done by television and national polls instead.

As a result, the candidates are already dramatically changing their strategies to run a national primary campaign so that they do well in the national polls that will decide their debate fate. Instead of visiting Iowa diners and holding New Hampshire town hall meetings, the candidates are making sure they get on national television. For Republicans, this means Fox News.

Iowa Republicans have already canceled the famous Iowa Straw Poll due to lack of participation from the candidates. New Hampshire Republicans are reporting fewer visits to their state, especially from the national frontrunners.

There are other forces that have conspired to weaken the position of Iowa and New Hampshire, too.

The proliferation of super PACs, with their ability to take nearly unlimited campaign contributions from wealthy donors, has changed the motivations of candidates. Instead of using early primary wins to attract new donors, the candidates are spending more time courting the big donors that could fuel their campaigns for months. One big check from a billionaire can mean more than a hard fought victory in one of the early states.

Indeed, finishing in the top two or three of Iowa or New Hampshire is no longer considered necessary to be a viable candidate.

Allowing states like Iowa and New Hampshire an outsized role in determining the presidential candidates was never ideal. Both states are unrepresentative of the nation as a whole. But the system did allow a glimpse into how the White House hopefuls handled themselves in intimate campaign settings with real voters.

That's no longer possible if the presidential campaign is waged primarily in television studios and in closed-door fundraising events with wealthy donors.