As he begins a tour of four industrial states, John Kerry says President Bush has failed to enforce trade agreements that protect U.S. workers.

The Democratic presidential candidate said Bush is not taking action to stop jobs from going overseas, such as aggressively filing unfair-trade cases with the World Trade Organization (search), or WTO.

"To engage and win in the global economy, we must not only open markets, we must ensure a level playing field for American workers," Kerry said in remarks prepared for delivery Monday. "As with most economic issues that impact American jobs and American workers, when it comes to enforcing our trade laws, this administration has been asleep on the job."

Kerry's speech kicks off a three-day bus tour through West Virginia, Pennsylvania, Ohio and Michigan. The four states combined have lost more than 470,000 manufacturing jobs during Bush's presidency, according to figures by the Bureau of Labor Statistics (search) cited by the Kerry campaign.

Democrats say Bush could be vulnerable in all four states because they have been hit particularly hard with job losses and record trade deficits. The states were hard fought during the 2000 election, with Bush winning West Virginia and Ohio and Democrat Al Gore winning Michigan and Pennsylvania.

Polls taken during recent weeks show Bush with a slight edge in Pennsylvania, but statistically tied with Kerry in the other three states.

A spokesman for the Bush-Cheney campaign, Steve Schmid, noted Monday that Kerry voted in the Senate for a number of international trade pacts, including the North American Free Trade Agreement (search).

"Now he has taken up an anti-free trade rhetoric because he believes it may benefit him politically. It's another example of John Kerry being both for and against a major issue," Schmid said.

A report released Monday by the Kerry campaign says Bush has presided over a "dramatic deterioration in our trade position," according to a summary.

"Year after year, he has consistently failed to represent U.S. interests in the global economy," the summary says.

With China, for example, the report says the administration has taken limited action on software piracy from China and the country's unfair trade policies for cotton, poultry, soybeans, wheat and high-tech products. It also says Bush has not provided relief to American workers and companies hurt by increased imports from China.

The United States had a trade deficit of $124 billion last year with China. That's the largest deficit ever recorded with a single country.

Kerry's report notes that the administration has filed just 10 WTO cases during his three years in office, compared with 65 during the last six years of the Clinton administration. Democrats in Congress have also complained about that record.

Kerry offered a six-part plan to enforce trade agreements, including efforts to strengthen worker's rights, eliminate abusive child labor and stop illegal currency manipulation. He said he would double the U.S. Trade Representative's budget for enforcement and create an advocacy office there for small businesses.

After kicking of his bus tour in Wheeling, Kerry was scheduled Monday to visit a mine in Moundsville, W.Va., and the All-Clad pots and pans factory in Canonsburg, Pa. On Tuesday, he planned to stump in the Ohio cities of Youngstown and Cleveland, and Wednesday he planned to visit Toledo, Ohio, and Ann Arbor, Mich.