Gov. Romney, Republican voters booed a U.S. soldier serving in Iraq; are you comfortable with that? No comment.

Gov. Romney, Ohio Republicans are fighting to undermine collective-bargaining rights; do you agree with them? No comment.

Gov. Romney, your top rival for the Republican presidential nomination is questioning the president’s citizenship status; is this a legitimate subject for debate? No comment.

I thought it would be worth asking the campaigns of the two frontrunners — Herman Cain and Mitt Romney –for comment on [Rick Perry’s birther comments]. Are they willing to condemn it? After all, Romney has vouched for Obama’s U.S. citizenship in the past and has made Perry’s unelectability central to his campaign, and it seems likely that Perry’s flirtation with birtherism will fuel doubts about whether he has the gravity and temperament to be a good general election candidate.

No luck.

Both campaigns declined to address Perry’s comments. “We’ll pass,” Cain spokesman J.D. Gordon emailed. A Romney campaign spokesperson also declined comment.

Remember, this isn’t one of those 11th-Commandment-style dynamics; Romney criticizes Perry comments all the time. But when Perry dabbles in unhinged conspiracy theories, the Romney campaign prefers to remain silent.

Greg Sargent added, by the way, that some major players in the party — Iowa Gov. Terry Branstad, Virginia Gov. Bob McDonnell, Karl Rove, and others — have all said Perry’s comments were, at a minimum, out of line.

So where’s Romney as his top rival is taking heat from within the party?

There’s going to come a point next year when the Obama campaign is likely to say, “Mitt Romney lacks the courage and the character to be a leader.” And the criticism will sting because it’s based in fact.

Romney can end this talk very easily and demonstrate that he’s more than a craven empty suit. There are some basic yes-or-no questions — Do you condemn the booing of honorable American soldiers? Would you endorse Paul Ryan’s budget plan? Do you support public workers’ collective bargaining rights? — that the former governor could answer directly without looking for wiggle room and without a bunch of caveats to cling to later.

He just doesn’t seem to have the guts.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.