WASHINGTON (Reuters) - The U.S. Senate will vote Tuesday on whether to open debate on a healthcare bill, U.S. Senate Majority Leader Mitch McConnell said on the Senate floor. The only way the Senate can actually consider ways to overhaul healthcare law is by opening a debate in the chamber said McConnell, a Republican. “That means voting to begin the open amendment process. That means voting to kick off a robust debate ... It means voting to proceed, and that will occur tomorrow.” 