WASHINGTON - Federal election regulators refused to ease limits on political advertising Tuesday, blocking an effort to let interest groups run radio and television ads mentioning elected officials within weeks of an election. The Federal Election Commission voted 3-3 on a proposal that would have allowed such ads as long as they addressed public policy issues and did not promote, support, oppose or attack a sitting member of Congress. Supporters of the change said they wanted to strike a balance between campaign ad restrictions and constitutional free speech guarantees. The measure failed on a tie vote with the commission's three...