ST PAUL (Minnesota) - REPUBLICAN White House candidate John McCain on Sunday defended his choice of Sarah Palin as running mate against Democratic claims she is dangerously inexperienced.

His wife Cindy meanwhile said Ms Palin credentials were bolstered by the fact that she hails from Alaska, the closest part of the US continent to Russia, to which her husband has adopted a tough political line.

'She's got the right judgement. She doesn't think like Senator Obama does that Iran is a minor irritant,' Mr McCain said an interview with Fox News on Sunday on the eve of the Republican National Convention here.

'She's been a commander in chief of the Alaska national guard,' he added, saying Ms Palin's son, who is in the US Army, is shortly to be deployed to Iraq.

'I'm proud of her knowledge,' Mr McCain noted.

Democrats and some political commentators have savaged his pick of Ms Palin, 44, a mother of five, over her lack of expertise in foreign affairs, saying she is too inexperienced to be a 'heartbeat' away from the presidency.

Mr McCain's wife Cindy also defended her husband's decision to turn to Palin, which electrified the crucial conservative powerbase in the Republican Party.

'She is heavily experienced in what she has done,' said Cindy McCain on ABC News This Week.

'The experience that she comes from is with what she?s done in the government,' she said of the former mayor and Alaska governor.

'And, also, remember, Alaska is the closest part of our continent to Russia. So it's not as if she doesn't understand what's at stake here.'

Democrat John Kerry however, a key ally of Democratic nominee Barack Obama, lashed out at the selection, saying on ABC that it proved Mr McCain was 'erratic'.

'John McCain's judgment is once again, put at issue, because he's chosen somebody who clearly doesn't meet the national security threshold, who is not ready to be president tomorrow.

'He's chosen somebody who actually doesn't believe that climate change is man made. He's chosen somebody who has zero - zero experience in foreign policy.'

Mr McCain has spent weeks questioning the inexperience of his Democratic opponent, first-term Senator Barack Obama, but appears to have defused those attacks with his choice of Ms Palin. -- AFP