This week's example: The former Massachusetts governor's refusal to endorse or oppose a deficit-cutting plan introduced by members of his own party, with a key deadline looming. Romney's cautiousness builds on the play-it-safe approach he has employed on issues ranging from Medicare overhauls to debt-ceiling negotiations, drawing criticism from GOP rivals and raising questions among uncommitted Republicans.
"It's a risky move to not take a position," said Michael Dennehy, a New Hampshire-based Republican operative who led Sen. John McCain's presidential bid four years ago. "When there's going to be intense scrutiny in these final seven weeks, voters are going to want to see someone who is showing their capacity to lead."
Romney's campaign says the GOP presidential hopeful has consistently articulated his economic plans.
But he has shown little willingness to inject himself into congressional debates on an issue he lists among his priorities, and which could have a profound impact on the next president's work. Instead, he has tended to focus on general economic principles such as lower taxes and less government spending, referring people to his 300-page book for a detailed version of how he would govern.
His rivals have at times adopted similarly cautious approaches. But they've sought to use Romney's reticence to take a position against him, launching in recent days a new round of criticism against the candidate.
"Now is not the time to be indecisive, it's time to exercise leadership," Michele Bachmann told The Associated Press in an email Saturday. Responding a question about Romney's strategy, she asked: "If you can't lead now, how will you lead as president?"
A congressional supercommittee has until Wednesday to produce a plan to cut deficits by at least $1.2 trillion over 10 years. Failure would trigger automatic, across-the-board cuts to the Pentagon and a wide variety of domestic programs beginning in 2013.
Republican Sen. Pat Toomey, R-Pa., recently offered a key concession — agreeing to limits on tax breaks enjoyed by people who itemize their deductions, in exchange for lower overall tax rates for families at every income level. A growing number of Republicans in Congress have embraced a tax overhaul package that increases revenues if paired with significant spending cuts.
But Romney says he's withholding his endorsement because he hadn't seen a specific proposal.
"I'm not going to sign up for it, of course, without reviewing it," Romney told radio host Hugh Hewitt on Friday. "I'd like to see us have lower tax rates and have a broader base. And it sounds like their idea is looking for a way of doing that."
"Mitt Romney soft-pedals the important issues facing this country," Perry spokesman Mark Miner said Saturday. "Washington doesn't need someone who's timid. They need someone like Rick Perry who's going to come in with a sledgehammer and shake things up."
Romney in some cases has been willing to embrace controversial policies. But he doesn't like to be the first to stick his neck out.
He started by applauding Ryan's "creative and bold thinking," but didn't say whether he actually endorsed the proposal. Then in early November, seven months after Ryan's plan was released, Romney released his own plan to overhaul Medicare in a way largely consistent with the congressman's original proposal.
Over the summer, Romney was equally non-committal during a debate over the nation's debt limit that nearly forced a government shutdown and threatened the government's credit rating. He stayed silent on the debt-ceiling deal during its negotiation, announcing his opposition to the final agreement just before lawmakers cast their votes.
His Republican competitors haven't forgotten.
"Whether it's the debt ceiling debate, the Ohio ballot initiatives, or military action in Libya, Mitt Romney has been either unwilling or unable to offer a clear position on issues important to voters," said Tim Miller, candidate Jon Huntsman's spokesman. "Leadership requires taking a stand on tough issues, even if it carries political risk."
Outside the Republican presidential nomination race, some politicians were more sympathetic.
"It's the inherent risk of being the front-runner: you tend to be a little more cautious in your approach on potentially controversial issues," said Kevin Smith, a Republican candidate for New Hampshire governor. "I think it's only an issue to the extent that the other candidates make it an issue."