But the core provision of the law would require that most garage, attic and playroom space be included in the floor area count.
Mr. McCain said that if necessary, he would attach only that core provision to other bills to get some campaign finance measure passed this year.
Republicans hope to attach their core provisions to the bills through amendments, but they acknowledged they face an uphill battle.
"We will accommodate more members, but not on the core provisions," he added.
The bill included seven core provisions.
The common-sense measure's nickname describes its core provision: States would be required to permit voter registration when people obtain or renew a driver's license.
The two chambers are in basic agreement on the bill's core provisions, including the narrow "conscience clause" that Mr. Bruno agreed to.
This will be the first time in history," the Senator said, "that we have repealed a core provision of the Social Security Act.
He said he was reversing himself to protect the agreement's core provisions banning unregulated soft money and third-party spending.
It is to be incorporated into the legislative framework of the European Union, and its core provisions will apply in all 27 Member States.