An editorial in London’s Times Online: The incredible shrinking elephant - Why moderate US Republicans must stand up for themselves.

The background to Mr Specter’s defection is a case in point. He is unquestionably an opportunist, abandoning the Republicans only when it became clear that staying with them would cost him his seat at next year’s mid-term elections. But before he jumped he was pushed hard by Pat Toomey, a conservative challenger from within the party, and by an increasingly powerful conservative faction known as the Club for Growth that Mr Toomey helped to found.

The battle between Messrs Specter and Toomey reflects a battle for the soul of the Republican Party that began long before Mr Obama stormed the White House. As a fiscal conservative, Mr Toomey’s insurgency was triggered by the expansion of state power and spending under President Bush, not his successor. His faction now helps to fund the campaigns of challengers to Republicans who it deems are insufficiently committed to the goals of lower taxes and smaller, more efficient government. But in the process it is undermining the campaign that Republicans should be fighting on similar themes but on a far larger scale - to rein in Mr Obama’s fondness for big government whenever the costs are unsustainable or the benefits moot.

America needs the Republicans, yet they are flirting with irrelevance. To return to relevance the party must be rebuilt as a coalition, not a clique. Its leaders must embrace its moderates, and its moderates - on everything from taxes to abortion - must stand up for themselves.