Senate expected to defeat GOP filibuster of gun-control legislation WASHINGTON, April 10 (UPI) -- Nine Republicans joining Democrats are expected to be enough to defeat a GOP plan to block the Senate from considering U.S. gun-control legislation, aides said. "It's incomprehensible to me that we would not move forward with debate and amendments on an issue this important to the American people," said Sen. John McCain, R-Ariz. Among the Republicans joining McCain in opposing the threatened filibuster by Tea Party-backed GOP Sens. Rand Paul of Kentucky, Mike Lee of Utah and Ted Cruz of Texas were Sens. Kelly Ayotte of New Hampshire, Saxby Chambliss of Georgia, Tom Coburn of Oklahoma, Susan Collins of Maine, Lindsey Graham of South Carolina, Dean Heller of Nevada, Johnny Isakson of Georgia and Mark Kirk of Illinois. Collins is co-sponsoring the bill's gun-trafficking and school-safety provisions. GOP Sens. Mark Kirk of Illinois and Pat Toomey of Pennsylvania also are expected to support debate on the bill, bringing the number of Republicans to at least 11, The Wall Street Journal said. Kirk and Toomey are completing negotiations with Sen. Joe Manchin, D-W.Va., on a bipartisan background-check proposal. Manchin said he hoped the bipartisan deal would be completed Wednesday. We're getting there, we really are getting there. Everyone's working," The Washington Post quoted him as saying Tuesday. "We're not there yet -- we're closer than we've ever been," said Sen. Chuck Schumer, D-N.Y., who is working with Manchin on changing parts of the bill. With backers of new gun-safety laws increasingly optimistic they will have the 60 votes needed to overcome the filibuster and bring the bill to the floor, Senate Majority Leader Harry Reid, D-Nev., said he would schedule a showdown vote for Thursday. "We're moving forward on this bill," Reid said. Reid earlier invoked his own father's suicide by gunshot to appeal for consideration of the legislation, which would also crack down on people who purchase firearms for those who are not permitted to own them. "The American people deserve a vote on this legislation," Reid said. The Thursday vote would formally start a political battle over the first major U.S. gun-control legislation in two decades. The Brady Handgun Violence Prevention Act, enacted Nov. 30, 1993, instituted federal background checks on firearm purchasers in the United States. The act was named after former White House spokesman James Brady, who was shot by John Hinckley Jr. during an attempted assassination of President Ronald Reagan March 30, 1981. It was followed by the Violent Crime Control and Law Enforcement Act, commonly referred to as the assault-weapons ban, that prohibited the manufacture for civilian use of certain semiautomatic firearms known as assault weapons. The assault-weapons ban expired Sept. No attempt to renew the ban has reached the House floor for a vote.