Republicans Round on Critics to Protect Palin

The Republicans set up a firewall around Sarah Palin today in a concerted attempt to choke off or deflect questions about her experience ahead of her prime-time national television debut.

Palin, who will make her first appearance at the Republican convention, has been embraced by the party's social conservative wing, injecting much-needed enthusiasm into their support for the candidate, John McCain.

However, in a sign that Republicans are feeling nervous about McCain's snap decision to make the virtually unknown governor of Alaska his running mate, party leaders and operatives began an aggressive new defence of the vice-presidential candidate. A new television campaign ad released today set out to build a case that Palin is a more effective agent of change than the Democratic nominee, Barack Obama. Further ads will contrast her experience overseeing state budgets with Obama's role as a junior senator.

The campaign said it would not answer questions about McCain's decision-making process before he settled on Palin. It also lined up party leaders to talk up her achievements.

An angry McCain, meanwhile, canceled a scheduled interview with CNN after an on-air clash between an interviewer and a press spokesman about Palin's foreign policy experience. There was also a parallel effort to squash discussion of her family life, including that of Palin's pregnant daughter Bristol, 17.

The entire Palin family was in the receiving line on the tarmac at Minneapolis airport to greet McCain on his arrival today, including Bristol and her boyfriend, Levi Johnston. McCain made a point of briefly chatting to the couple.

Aside from that brief appearance and a walk around of the convention stage earlier in the day, Palin remained in hibernation - leaving it to her fellow Republicans to rally to her defence.

Officially, the campaign is convinced that Palin will appeal to centrist voters - especially women - despite the steady drip feed of potentially damaging revelations about her, and her uncompromising stance against abortion, gay rights and sex education, as well as providing environmental safeguards in the Alaska wilderness.