Liz Sidoti: Can America's big two rise to challenge of new politics?

SINCE the birth of the American political party, its primary mission has been to amass power by recruiting candidates, raising money and spreading messages. In short, a holding company that elects people – with a monopoly for a century and a half by Democrats and Republicans.

But a chain of events in recent history – from the internet's ascent and a Supreme Court ruling on political money to today's maelstrom of voter anger – is changing things.

The major political parties are inching now towards a decision point: change with the times or risk diminished influence.

Results of primary elections in Kentucky, Pennsylvania and Arkansas last week illustrated the threat the party establishment faces. Elections are becoming fragmented as populist coalitions thwart the will of Republican and Democratic leaders.

"People have decided they don't need big centralised gatekeepers to make decisions for them," said Alex Castellanos, a former Republican National Committee adviser. "It's a bottom-up world, not a top-down world any more. And people are empowered to cut out the middleman."

To some degree, this is democracy at work. People rise up, make their voices heard and choose leaders without being told by Washington party bosses whom to support. But the outcome could mean it's harder to get things done.

More insurgent politicians in Washington could make it tougher accomplishing anything in Congress, where building coalitions is already tough enough.

Karen Finney, a former Democratic National Committee spokeswoman, said: "The parties need to rethink how they reach out to supporters and engage supporters. That's part of how they will stay relevant."

Both parties have been studying last week's polling results intently.

In Kentucky, the conservative "tea party" coalition rallied behind political novice Rand Paul for the Republican Senate nomination over the candidate preferred by Senate minority leader Mitch McConnell in his home state and the Senate Republican campaign committee.

In Arkansas, unions split from President Barack Obama and the Democratic Party, pouring money and manpower into a Senate primary race to force White House-backed Senator Blanche Lincoln into a run-off.

Pennsylvania's Democratic voters rejected party-switching Senator Arlen Specter, a five-term institution and recipient of campaign help from Mr Obama, in favour of a lesser-known congressman who rejected White House appeals to abandon his candidacy.

Look around the political landscape and there's ample evidence the parties are being challenged, if not supplanted.

The Supreme Court recently cleared the way for corporations or unions to run campaigns calling for the election or defeat of candidates. The ruling means parties will lose some control of election-season messages.

Candidates are creating bases of support separate from the parties by harnessing technology and feeding the public's thirst to be connected. The president built his "Obama for America" coalition in 2008, and Republican Sarah Palin, the former Alaska governor and 2008 vice-presidential candidate, now has legions of Facebook and Twitter followers. Countless online communities have popped up to force political change by drafting candidates into races and helping their campaigns.

Attempts to create third parties of comparable strength to the big two have failed miserably. Independent candidates still face fierce battles in getting elected. That makes it difficult to see how the Democratic and Republican parties could become obsolete.

Certainly, political parties now have an opportunity to retain their power. But how will they approach the challenge?

Sidney Milkis, a University of Virginia political scientist, said: "Maybe what will happen is the parties will become better connected to the citizenry, and the organisations will become less centralised – and maybe more reflective of how the rank and file feel about politics."

Whatever the political landscape turns out to be, there's no doubt it will contain a lot of voices saying a lot of different things. For the parties, the challenge is how to harness those voices and stay relevant in the new social order that is 21st-century politics.

• Liz Sidoti is a political reporter for the Associated Press.