They say Reid, who in July accused Romney of not paying taxes for a period of 12 years, has engaged in political activity that would violate federal rules if not for the Speech and Debate clause of the Constitution.

Reid pounced on Romney on Wednesday for remarks he made earlier this year characterizing “47 percent” of the nation as people who believe they are victims and who rely on government handouts. …

“He’s campaigning on the Senate floor. It’s the taxpayer-funded Senate floor. The speech had nothing to do with the Senate. It was a pure campaign speech. You couldn’t give it in the rotunda. You couldn’t give it in my office. It’s a taxpayer-funded building,” said a senior Senate Republican aide.