Republican presidential candidate John McCain compared Barack Obama to socialist leaders in Europe yesterday, saying his rival wants to raise taxes on the wealthy to give money to the poor.

McCain, an Arizona senator, tried to erode the advantage Obama has built on the issue of the economy as he spent the day campaigning in traditionally Republican states that are now up for grabs -- North Carolina and Virginia.

Obama drew 100,000 people to a rally at the iconic Gateway Arch in St. Louis, his biggest crowd yet, according to his campaign, which cited a local police official.

Obama accused McCain of mischaracterizing his tax plan. He also said the Republican's economic program put the interests of the well-connected above those of waitresses and janitors.

In a radio ad, McCain said Obama would raise taxes on some people in order to give government cheques to others.

"Barack Obama's tax plan would convert the (Internal Revenue Service) into a giant welfare agency, redistributing massive amounts of wealth at the direction of politicians in Washington," the Republican candidate said.

"At least in Europe, the socialist leaders who so admire my opponent are upfront about their objectives. They use real numbers and honest language. And we should demand equal candor from Senator Obama," McCain said.

McCain was referring to Obama's promise of a tax cut to families earning less than $250,000. Some workers who do not earn enough to owe federal income taxes would get a refund on money they contribute in Social Security payroll taxes.

The Obama campaign pointed out that the tax credit at the center of McCain's health care plan is also refundable for low-income workers.

With just over two weeks left before the November 4 election, Obama leads McCain in national opinion polls and in many of the battleground states that will be crucial to the the race.

The worst financial crisis in a generation has boosted Obama, whose calm demeanor has won over some voters anxious about the economy.

In hopes of overtaking Obama, McCain has focused heavily on the story of an Ohio man dubbed "Joe the Plumber," who raised questions about Obama's tax plans and became an invisible third member in the candidates' last televised debate this week.

"We learned that Senator Obama's economic goal is, as he told Joe, is to 'spread the wealth around,'" McCain told a rally in Concord, drawing loud boos from the crowd.

"Senator Obama believes in redistributing the wealth, not in policies that grow our economy and create jobs and opportunities for all Americans."

In his third and final debate with Obama this week, McCain cited Joe Wurzelbacher as an example of someone who would be hurt under Obama's tax plan. Wurzelbacher said he intended to buy a plumbing business but believed he would receive a tax increase under Obama's economic plan.

Based on what Wurzelbacher has said publicly about his income, the Obama campaign said he would be eligible for a tax cut, not a tax increase, under the Democrat's proposal.

Obama says his tax plan would give a break to 95 percent of all workers and 98 percent of small business owners.

"John McCain is so out of touch with the struggles you are facing that he must be the first politician in history to call a tax cut for working people "welfare," the Democratic candidate said at the St. Louis rally.

"The only "welfare" in this campaign is John McCain's plan to give another $200 billion in tax cuts to the wealthiest corporations in America," Obama said.

The St. Louis event was Obama's largest in the United States, the campaign said. The only event he has held of comparable size was in July in Berlin's Tiergarten Park, where throngs of Germans gathered to hear him speak about transatlantic relations.

Obama, who dropped by a volunteer headquarters in Kansas City yesterday to help work the phones, was to hold a rally in that city in the evening.

A Rasmussen poll on Friday showed Obama leading McCain by 6 percentage points in Missouri, 52 to 46 percent. The poll, with a margin of error of 4.5 percentage points, showed that McCain was favored by voters in the state during much of the summer.

President George W. Bush won the state in both 2000 and 2004.