The mudslinging continues in presidential ads statewide.

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A recent ad from the Barack Obama campaign goes after John McCain for alleged ties to big oil.

WISC-TV found that the money trail doesn't lead as directly as the ad claims.

Oil companies play the villain in the latest Obama ad and thus McCain by connection.

But we find the ties Obama tries to make from big oil to McCain needs some exploration.

"Every time you fill your tank the oil companies fill their pockets. Now big oil is filling John McCain's campaign with $2 million in contributions," said the ad.

This is misleading. While oil companies have raked in record profits, the actual corporations haven't given a dime to candidates. That's been illegal for decades.

But employees of those corporations can. The Center for Responsive Politics, a nonpartisan group that tracks fundraising, and which the ad cites here, currently estimates McCain's contributions from people who work in the oil and gas industry or company-sponsored political action committees at $1.3 million - - not $2 million, a WISC-TV analysis found.

However, many of the same people have given money to the "McCain Victory Fund." Parts of those donations go to the campaign, the rest to the Republican National Committee. When you add those funds, the total tops $2 million.

And despite the fact that the RNC is running ads, the money technically wasn't donated to McCain's campaign.

And for the record, CRP said Obama has accepted nearly $400,000 in donations from oil and gas, WISC-TV found.

The ad continued, "Because instead of taxing their windfall profits to help drivers. McCain wants to give them another $4 billion in tax breaks."

This is also misleading and is a claim we've talked about in a previous Obama ad.

McCain doesn't just want to cut taxes for oil companies, a WISC-TV analysis found. He wants to lower the corporate tax rate by 10 percent which would give breaks to big oil but also many other companies like GM or Wal-Mart.

Obama ends by saying the answer is a windfall profits tax on oil companies, that can in turn become a rebate for consumers.

McCain said the tax would only increase dependence on foreign oil.

The congressional research service in a 2006 report found the similar tax enacted in 1980 did exactly that by reducing domestic production by about 13 percent.

But the report said it did cut into the profits of the oil companies.