IOWA CITY, Iowa — The campaign for tighter gun laws that inspired unprecedented student walkouts across the country still faces an uphill climb in a majority of states, an Associated Press review of gun legislation found.The AP survey of bill activity in state legislatures before and after the Parkland, Florida, school shooting provides a reality check on the ambitions of the "Enough is Enough" movement. It suggests that votes like the one in Florida, where Republican lawmakers defied the National Rifle Association to pass new gun regulations, are unlikely to be repeated in many other states, at least not this year.The student-led activism might yet lead to future reforms, but for now, the gun debate among most lawmakers still falls along predictable and largely partisan lines, with few exceptions, according to the analysis.Because Congress shows no sign of acting, state legislatures dominate the national debate over guns. And major changes won't be easy to achieve in statehouses that are mostly controlled by the gun-friendly GOP.Republicans have sponsored more than 80 percent of bills that would expand gun rights, while Democrats have introduced more than 90 percent of bills to limit them.