The news that our trade with China has been bad for the American middle class has finally reached the U.S. Senate. On Monday, the Senate will take up legislation that would impose tariffs on Chinese goods so long as China depresses the value of its currency. Despite the partisan polarization that grinds lawmaking to a halt these days, the bill’s support is thoroughly bipartisan, with sponsors ranging from such conservative Republicans as South Carolina’s Lindsey Graham to liberal Ohio Democrat Sherrod Brown. The legislation is expected to clear the Senate’s 60-vote hurdle for a floor vote and move on to the House.

For students of America’s deranged romance with free trade, the fact that the Senate is willing to take on China is little short of amazing. Since the 1980s, the House has been the legislative body where epic battles have been waged over the free-trade agreements that have decimated American manufacturing. The impact of factory closures on congressional districts is generally too big for representatives to ignore. Local manufacturers and bankers, no less than local union members, complain to their House members; when the town’s biggest employer leaves, grief knows no party. Senators, on the other hand, move in a larger world, one where Wall Street contributors and Washington pundits assure them that free trade is invariably good. So while the House has been home to furious fights over NAFTA, CAFTA and extending permanent normalized trade relations to China, the Senate has long passed such measures with much less fuss and sublime indifference to the consequences.

But the consequences can no longer be denied. Between 2001 and 2010, the U.S. trade deficit with China cost Americans 2.8 million jobs, according to a report by economist Robert Scott, issued last week by the liberal Economic Policy Institute. Most of those jobs — 1.9 million — were in manufacturing, and of those, almost half were in computers and electronics.

This wasn’t simply the consequence of China’s cheaper labor or more generous corporate subsidies. As China’s productivity soared during the past decade, the value of its currency should have risen correspondingly. Instead, China purchased dollars, which had the effect of depressing the yuan and making Chinese exports about 28 percent cheaper than they would be if the yuan had been allowed to appreciate, William Cline and John Williamson found in a study for the centrist Peterson Institute for International Economics.

Data like these have been floating around for years, of course. Until now, however, the Senate has remained largely impervious to the evidence of Chinese cheating and American decay. But elite opinion, which the Senate does heed, is finally catching up with mass opinion on whether losing our manufacturing base is a bad thing. An influential July 2009 article in the Harvard Business Review by economists Gary Pisano and Willy Shih argued that losing manufacturing meant losing our edge in innovation, that the relationship between research and production was reciprocal. This would not have come as news to Thomas Edison, but few on Wall Street or in corporate boardrooms the past two decades believed that America’s prosperity and dynamism required the retention and renewal of manufacturing.

Even now, it’s hard to find many there who believe that. Finance has fattened on manufacturing’s decline, as consumer debt replaced producer wages as the fuel that makes America run (and crash). And finance still has friends in Washington. The U.S. Chamber of Commerce, which represents many American corporations that make their products in China, opposes the Senate legislation. Ironically, now that the Senate is on the verge of passing the bill, Politico reports that House Republican leaders have no intention of bringing the bill to a vote. House Speaker John Boehner and Majority Leader Eric Cantor don’t want to jeopardize their assiduously cultivated Wall Street funding — even though polls show rank-and-file Republicans want a more assertive economic posture toward China. That’s doubtless one reason why Mitt Romney has vowed to impose tariffs on China the day he becomes president.

Our current president, meanwhile, has maintained a discreet silence on the Senate bill. Barack Obama has said that he wants the United States to double its exports over the next five years, but expanding American manufacturing on that scale can’t be done if China continues to eat our lunch. No issue divides Wall Street from Main Street more than trade, and winning Main Street’s support in next year’s election will require Obama to stand up more than he has for America’s industrial interests. Hell, even the Senate has figured that one out.