Virginia Senate candidate Tim Kaine (D) suggested Thursday that he would be open to considering a minimum tax on Americans.

Kaine, the former governor of Virginia and former Democratic National Committee chairman, said during a debate versus Republican opponent George Allen that he would be open to a minimum tax proposal.

Evan Vucci / AP

Republican candidate George Allen, right, speaks as Democratic candidate Tim Kaine looks on during a Senatorial debate for the Virginia U.S. Senate seat on Thursday, Sept. 20, 2012 in McLean, Va.

"I would be open to a proposal that would have some minimum tax level for everyone," Kaine said when pressed by debate moderator David Gregory on whether Americans should face a minimum federal income tax. "But I do insist, many of the 47 percent that Gov. Romney was going after pay a higher percentage of their income in taxes than he does."

Kaine's remark came during a broader exchange about Republican presidential nominee Mitt Romney's comments that he couldn't count on about 47 percent of Americans to vote for him because they pay no income taxes and are "dependent" on government. Romney made those comments in May, which were surreptitiously recorded at the time and publicized this week.

Romney's controversial suggestion has become an issue in several competitive Senate races, such as Connecticut and Massachusetts, where Republicans Linda McMahon and Sen. Scott Brown have (respectively) distanced themselves from Romney.

Allen, the former Republican senator who lost his re-election bid in 2006, didn't as sharply distance himself from Romney. "I have my own view," he said about Romney's comments before pivoting to speak about jobs.

The Kaine-Allen race is one of the most competitive in the nation this year; its outcome could foretell control of the Senate in the next Congress. Republicans need to achieve a net gain of four seats to win back the majority in the Senate.

Last week's NBC News/Marist/Wall Street Journal poll of Virginia voters found the Senate race tied, at 46 percent apiece for Kaine and Allen.

Whether Kaine's comments today have any lasting effect will play out in the next days and weeks, though Republican observers of today's debate -- which was organized by NBC-Washington affiliate WRC -- immediately took note of the minimum tax comments.