By ALAN FRAMWASHINGTON (AP) a¿¿ A sprawling Democratic bill expanding health, education and other benefits for veterans easily cleared an early Senate hurdle on Tuesday. But the election-year measure still faces an uncertain fate as Republicans battle to make it smaller and find ways to pay for it. By a 99-0 vote, senators agreed to begin debating the legislation, which sponsor Sen. Bernie Sanders, chairman of the Senate Veterans Affairs Committee, says would cost $21 billion over the coming decade. That opened the door to what is likely to be days of GOP efforts to pare it down and lessen its impact on budget deficits. By the time the Senate reaches a final showdown vote, the bill could confront GOP lawmakers with an uncomfortable campaign-season test over curbing spending for the nation's 22 million veterans and their families. Most veterans groups support the legislation, and the voting bloc they represent is a potent one that both parties usually try to avoid offending. Some Republicans consider Sanders' legislation an election-year ploy aimed at forcing them to take embarrassing votes. They say the measure is too expensive and would provide so many new benefits that it would clog up a system already overburdened with veterans seeking health care and other benefits. Sen. Richard Burr of North Carolina, top Republican on the Veterans panel, said it was irresponsible "to talk about dumping more people on a broken system, to talk about asking those who've already waited so long to wait longer because of our actions." But Sanders, I-Vt., said, "We have the moral obligation to do the very best we can for veterans." Republicans were demanding a chance to offer amendments a¿¿ particularly a GOP substitute Burr said was less costly and would be paid for with savings culled from veterans' programs. Burr's proposal also included language imposing new sanctions on Iran because of its nuclear program, which President Barack Obama has urged Democrats to resist.