Why Republicans should worry

It is true that the most famous scalp to fall on Tuesday night was that of Senator Arlen Specter,who has spent 30 years in the Senate. For a brief period Mr Specter gave Mr Obama his supermajority in the upper chamber. He also cast the deciding vote on last years stimulus bill. But his defeat by Joe Sestak in Pennsylvanias Democratic primary cannot be construed as a defeat for the party itself. After all,Mr Specters chief handicap was that he was a Republican until crossing the aisle just over a year ago. The Democrats national leadership tried to save him. But since turncoats are unpopular,it is by no means certain that Mr Sestak,an impressive congressman and former naval officer,will fare worse against the Republican Patrick Toomey in November.

The Democrats can meanwhile draw encouragement from the only fight on Tuesday that took place between parties rather than within them. Their man won the special election to fill the House seat left vacant in Pennsylvanias 12th congressional district by the death in February of John Murtha,a long-serving Democrat. Having worked for Mr Murtha,Tuesdays victor,Mark Critz,held out the promise of continuing his bosss legendary knack of delivering Washington pork to the Pennsylvania rustbelt. The Republicans had sought to counter Mr Critz by turning the race into a referendum on the Obama administration. At times during the campaign the polls suggested they were close to success. In the end,however,Mr Critz beat the Republicans Tim Burns,a self-made local millionaire,by a respectable margin of 53 to 45.

A defeat there would have been wretched for the Democrats. White working-class districts such as Pennsylvanias 12th no longer account for more than about a quarter of the partys seats in Congress. But holding on to them is essential if the party is to remain in power. Otherwise,says Bill Galston,a former party strategist and now a senior fellow at the Brookings Institution in Washington,DC,the Sisyphean task of constructing a Democratic majority will come to its Sisyphean end with the rock rolling back down the hill. But whether Mr Critzs success can be repeated in his own or similar districts in November remains an open question. It is telling that he had to be careful in his campaign to distance himself from Mr Obama,disavow the liberal label and insist that if he had been in Congress at the time he would have opposed health reform,the presidents foremost domestic initiative.

In Arkansas the primaries brought less comfort to the Democrats national leadership. In a three-way race Blanche Lincoln,a Democratic centrist and sitting senator,failed to collect enough votes to avoid having to confront her main challenger,the states lieutenant-governor,Bill Halter,in a run-off next month. Senator Lincoln had antagonised the unions by wavering on health reform and opposing the Employee Free Choice Act,a bill that would help workers to unionise firms without a secret ballot. Her reputation as a Washington insider told against her at a time when Congress and the federal government are highly unpopular. But there are many parts of the country in which the Democrats will need to be able to run centrists like her if they are to do well in November.

It is the Republicans,however,who may worry most about the price they could pay in November for internal ideological splits. In Kentucky the retirement of the junior senator,Jim Bunning,produced a humdinger of a fight between the party establishment in the person of Trey Grayson,Kentuckys secretary of state,and Rand Paul,an outsider and ophthalmologist with little previous experience in politics. Mr Grayson was handpicked for Mr Bunnings seat by the states senior senator,Mitch McConnell,who happens also to be the Republican leader in the Senate. All Dr Paul had going for him was a famous father the Texas libertarian,Ron Paul,who sought the Republican presidential nomination in 2008 and may do so again and the support of the tea-party movement that has electrified Republican politics this year.

That proved more than enough. Being an outsider did not stop Dr Paul from routing Mr Grayson by 23 points. And this was only the latest of a string of successes for candidates supported by the tea-partiers. Earlier this month,in another stunning upset,Republicans in Utah dumped Bob Bennett,a three-term sitting senator whose solid conservative credentials were apparently no longer good enough to satisfy the partys local activists. And in Florida in April opposition from the tea-partiers prompted the Republican governor,Charlie Crist,to quit the party altogether. He now intends to run for the Senate in November as an independent.

The impact of the tea-partiers is a decidedly mixed blessing for the Republicans. On the one hand,the party benefits from the passion and dollars this widespread grassroots mutiny against big government is able to inject into local campaigns. On the other,they are in danger of pushing the Republicans well to the right of the mainstream. Dr Paul,like his father,is a genuine radical who believes in paring government down to the bone.

The tea party is huge, Dr Paul declared in his victory speech. It will certainly have a huge influence on the tactics of Republicans thinking of running for the partys presidential nomination. But since only registered Republicans were allowed to vote in Kentuckys closed primary,it is difficult to know how many other voters,even in Kentucky,will plump for a candidate who threatens to slash their entitlements and hankers after the gold standard.

With six months to go until the mid-terms,and with politics haunted by a powerful mood of anti-incumbency,plenty of political surprises no doubt remain in store. This week alone brought the resignation of Mark Souder,a Republican congressman from Indiana who had an affair with a staffer with whom he had recorded an appeal for sexual abstinence. Richard Blumenthal,the Democratic senatorial candidate for Connecticut,is in trouble for having conveyed the impression unwittingly,says he that he served in Vietnam,when in fact he had obtained several deferments. Such misdemeanours will do nothing to change the low opinion Americans have of their present lot of politicians.