Mitt Romney and President Barack Obama have traded superheated barbs in the past week over who would be tougher on China’s trade practices, but neither has tried to take advantage of a Senate-passed currency manipulation bill that has been sitting on the House calendar for almost a year.

Instead, Romney has tried to outflank Obama by vowing to label China a currency manipulator on his first day in the Oval Office, and Obama has parried by blasting Romney’s record on outsourcing and touting his own record of filing enforcement actions against China, including one this week on auto parts subsidies.

But the bipartisan China currency bill, which passed the Senate last October and could lead to steep tariffs on Chinese goods, remains bottled up by Speaker John Boehner (R-Ohio) despite having more than enough co-sponsors to pass – and that’s where it’s likely to stay.

In an unusual, de facto alliance, the White House, top House Republicans and an array of powerful business interests – including the U.S. Chamber of Commerce – think launching a broad-scale assault on China’s currency policies is not worth the risk of a full-blown trade war.

Like Romney this year, then-Sen. Obama said he would go to “the mat” on the issue five years ago. And despite his rhetoric, Romney so far has not called on Boehner to put the bill up for a vote.

Boehner, for his part, has repeatedly called the currency bill “dangerous” while lobbing the issue back in the White House’s court. Why bring up the bill if the president won’t say he’ll sign it?

The White House’s public stance appears to be deliberately vague. The president has been caught between many of his allies on the left, who want him to wield the biggest possible stick, and concerns about Chinese retaliation and the ensuing effect on a weak U.S. economy. White House Press Secretary Jay Carney last year said the administration shares the goals of the legislation but has concerns about it affecting other international obligations.

The reality, however, is that the president has done nothing to advance the bill. Nor has Obama been willing to label China a currency manipulator under his administration’s existing authority, as Romney notes frequently on the campaign trail. That’s frustrated some of Obama’s allies, including Sen. Sherrod Brown (D-Ohio), who earlier this year accused the administration of again giving China a “free pass.” It’s a criticism the Romney camp has eagerly disseminated to reporters.

Some Democrats believe Obama missed an opportunity to put House Republicans on defense.

“I think there’s broader frustration that Boehner hasn’t scheduled a vote, but yes, there’s also some frustration the administration hasn’t taken up the cause either,” one Democratic aide said.

And Senate Democratic leaders are in a bit of a political pickle: Champions of the bill, including Senate Democratic Conference Vice Chairman Charles Schumer (N.Y.), have pushed Boehner to move on the bill, but they don’t want to look as if they’re breaking from the administration less than two months out from the elections. Schumer could use the latest trade squabble as an opportunity to go to the floor and call on Boehner to pass the bill again, but that would focus exclusively on the GOP, a Senate Democratic leadership aide said.

The aide said there has been “communication and consultation” with the White House on China “issues at large, like the trade cases,” but the aide doesn’t see the White House changing its tune on currency.

The Romney campaign, meanwhile, has been running ads and making the issue a regular topic on the campaign trail. Romney even joked this week that he would have run ads earlier if he thought it might get Obama to take action on China.

Sen. Jeff Sessions (R-Ala.), who broke with most in his party to champion the currency bill, said Romney should get credit for taking on interests in his own party.

“The Wall Street free-traders get nervous any time you stand up for legitimate American interests,” he said.

Sessions blames Obama’s passivity for the bill getting bottled up in the House. “Had he pushed it, I don’t think the House could have avoided taking it up, and I think it likely would have passed. For the president now to claim he’s doing something significant on trade rings very hollow.”

Sessions called Obama’s launching an enforcement action on auto parts an attempt at finding “cover” on the issue, and he said Romney would have more credibility to confront China.

“Gov. Romney understands trade, economics and business in a way that President Obama can’t begin to touch,” Sessions said. Sessions said he thinks Romney has made his threat seriously and would follow through if he’s elected. “I don’t think he made that commitment recklessly,” he said.

But others are betting Romney would punt in the end.

“It’s just naked pandering to the electorate; it’s as simple as that,” said Andy Roth, vice president of government relations at the conservative Club for Growth. “Don’t bet the farm on that happening if he’s elected.”

Roth said Romney’s stance comes down to politics, likening it to Obama’s unfulfilled threat to withdraw from NAFTA four years ago during the Democratic primaries. “This is how you get votes in Ohio,” Roth said. “It’s unfortunate, but true. … We need somebody to be courageous and show that you can win by supporting free trade.”

House Democrats have repeatedly sought to bring up the bill and have even circulated a discharge petition to no avail.

“This bill has more than 250 co-sponsors. So much for Speaker Boehner’s promise that the House will work its will,” another Democratic aide said.

Meredith Shiner contributed to this report.