ST PAUL, Minnesota, (AFP) - Republican White House nominee John McCain on Wednesday attacked Barack Obama's achievements as "meagre" and said his Democratic foe did not know how the world, or the US military, worked. The Arizona Senator, who was set to be formally nominated as his party's White House champion later Wednesday, also defended his under-fire running mate Sarah Palin, saying she had been "vetted" by voters in her home state Alaska. He said in an interview with "ABC World News" that Obama's achievements were "very meagre" in comparison to those of Palin who was a smalltown mayor and is now Alaska Governor. "Senator Obama has a campaign to run, Governor Sarah Palin has 24,000 employees in the state government," McCain said. "She's responsible for 20 per cent of the nation's energy supply.  "I'm entertained by the comparison and I hope we can keep making that comparison that running a political campaign is somehow comparable to being the executive of the largest state in America." McCain, who makes his keynote speech to the Republican National Convention on Thursday, said his resume was far more appropriate to the job of president than that of Obama. "I understand and I have the knowledge and the background and the experience to make the right judgments," McCain said in the interview. "Senator Obama does not. He was wrong on Iraq. He underestimated Iran. He has no knowledge or experience or judgment. He doesn't know how the world works nor how the military works. I do and I can lead and I'll secure the peace," McCain said.