As the economic stimulus package grinds its way through the Senate, business leaders are pondering the massive deficits to come and asking the trillion-dollar question: Where’s the funding going to come from?

If your business has extensive operations outside the United States, a chunk of it may be coming from you.

At various stops along the campaign trail, then-candidate Obama announced his intention to “stop giving tax breaks to corporations that send American jobs overseas.” The campaign’s comprehensive tax plan was more specific, noting that Obama planned to target “international tax loopholes, including reforming deferral to end the incentive for companies to ship jobs overseas…”

I wouldn’t be too surprised if “reforming” turns out to mean “eliminating” the deferral, which allows offshore subsidiaries’ profits to grow free of U.S. income tax prior to repatriation. It’s a tax break that U.S.-based multinationals have long relied on to mitigate the pain of “double taxation” by the United States and the foreign jurisdiction.

Tax execs are convinced that these are not just empty campaign promises. In a new survey from Washington, D.C.-based law firm Miller & Chevalier, close to 70 percent said they that an increase in taxation of international operations — for example, a reduction in foreign tax credits, elimination of deferral, or transfer pricing changes — will be “among the leading sources tapped to pay for Congressional tax initiatives” this year.

Many of these tax pros see any such moves as particularly damaging to their business. When asked which of seven business tax revenue sources would have the most unfavorable impact on their organization, 36 percent cited an increase in taxation of international operations. That’s more than twice the number who chose the next-most-feared option, elimination or reduction of LIFO inventory benefits.

And, as if that’s not enough to worry about, three-quarters of the execs polled think that Congress will press the IRS to step up scrutiny of international business operations in 2009.

On the bright side, President Obama has signaled that he may support a proposal by House Ways and Means Committee Chairman Charles B. Rangel to cut the corporate income tax rate from 35 percent to 30.5 percent (and Rangel has said he can envision going as low as 28 percent). But for corporate taxpayers with big operations abroad, the new administration’s tax policy will likely be a case of one hand giving and the other taking away.

The Miller & Chevalier report is available here.