US primaries deal blows to both parties
Primary contests to select the Democratic and Republican party candidates for November's mid-term elections are under way. But as the BBC's Katie Connolly in Washington reports, voters do not always back those favoured by the party bosses.
Washington pundits were determined to see Tuesday's primaries as the latest evidence of anti-incumbent fever in the US - but the results were far from conclusive.
Democratic Senator Arlen Specter's loss in Pennsylvania is a blow to the White House political team who threw their support behind him.
Just as in the state governorship contests in New Jersey and Virginia last year, White House backing wasn't enough to push their candidate over the line.
But Joe Sestak's victory over Mr Specter should not be construed as an outright rejection of President Barack Obama and his administration.
Mr Specter's situation was unique: he had served almost five terms as a Republican, albeit a relatively moderate one, and thus had a long history with Pennsylvania voters.
In changing to the Democratic party a year ago, Mr Specter fed voter distrust - a feeling the Sestak campaign capitalised on with advertising pointing to statements where Mr Specter indicated the switch had been motivated by his own political survival.
It is likely Mr Specter would have lost had he remained a Republican, an indication of the mood of American voters, which suggests that candidates who do not adhere to party lines will be in for a rough time in November's mid-terms.
In Arkansas, Democratic Senator Blanche Lincoln will be feeling that same sentiment today.
Sen Lincoln is a moderate whose public equivocations over the Democratic healthcare reform bill - along with her rejection of cap-and-trade energy legislation - has cost her support from the party's base.
She failed to get 50% of the vote on Tuesday night, and so will be forced into a run-off election to decide the Democratic nominee in November.
That run-off will absorb precious time and resources for the Democratic candidates, who will spend their time criticising each other while fired-up Republicans are free to concentrate on mobilising their voters.
In Kentucky, Republican Rand Paul's win over Trey Grayson, driven largely by activists from the conservative Tea Party movement, shows that if voters are indeed angry at incumbents, their fury is not solely reserved for Democrats.
The Republican establishment, most notably Senate Minority Leader and senior Kentucky Senator Mitch McConnell embraced Mr Grayson, as did former Vice-President Dick Cheney and former New York Mayor Rudy Giuliani.
Yet Sen McConnell's endorsement held no more weight than Mr Obama's, it seems. Tea Party fervour was too great, illustrating the importance of voter enthusiasm in getting voters to the polls in mid-term election years.
But there was only one election that sent the winner to Washington on Tuesday, and that was the contest to replace the late John Murtha, a House representative from Pennsylvania.
Democratic candidate Mark Critz beat Republican Tim Burns handily, buoyed in part by increased Democratic turnout as a result of the heated Senate primary race.
Moreover, Republicans' attempts to portray Mr Critz - who had worked for Mr Murtha in Washington for a decade - as a Washington insider did not appear to resonate with voters.
Instead, with help from the Democratic Congressional Campaign Committee, a centralised organisation which supports House candidates, Mr Critz ran a tight campaign operation focusing on local issues.
He even had former President Bill Clinton campaigning for him in his district, a blue-collar area that notably backed Democrat John Kerry in 2004 but went for Republican John McCain in 2008.
Both parties will study that race for lessons for November.
Meanwhile, Washington pundits will no doubt start betting on how many blue-collar districts Bill Clinton will be asked to visit before November.