WASHINGTON (AP) — Hillary Clinton on Wednesday will unveil a proposal for a new "exit tax" aimed at cracking down on corporate inversions, a practice that permits U.S. companies to merge with corporations overseas to lower their tax bill. The Democratic presidential front-runner will propose spending the revenue raised by the new tax to boost manufacturing jobs in the U.S., campaign aides said. The November announcement of a plan to merge drug-makers Pfizer and Allergan to create the world's biggest pharmaceutical company reignited a fierce political debate over whether such deals should be permitted. Democrats favor immediate action and are seeking to use the issue as a political wedge ahead of next year's presidential election, accusing the GOP of protecting corporate loopholes. Clinton's main rival for the Democratic nomination, Vermont Sen.