Another problem for Democrats is geography: Progressive activists form a consistent critical mass only in deep-blue cities or states — which limits their ability to win over moderate voters in other parts of the country. Universities and progressive think tanks like the Roosevelt Institute and Economic Policy Institute abound with innovative ideas about how to narrow the income gap, expand and lower the cost of health care, put together a Green New Deal, curb the power of Amazon and its corporate ilk. But their plans lie fallow without a well-organized constituency of working-class Americans that can elect enough politicians to turn them into law.One can detect some shoots of a potential revival. Workers at Starbucks, a rising number of websites and periodicals, and high-tech companies like Google and Apple are joining unions and fighting to get their employers to recognize them. And most Americans appear to share their esteem for institutions whose purpose has always been to bring a semblance of democracy to the job. In recent polling, organized labor is more popular than it has been since the mid-1960s.However, as with social media, to “like” a group does not mean one will take action to join or build it or even know how to go about doing either. Most contemporary Americans see unions as a good idea, but not an institution to which people they know belong and cherish. With union membership down to only a tenth of the work force nationwide, only government employee unions remain a powerful factor in most Democratic campaigns.Still, progressive politicians who consistently talk about class inequality can win, even in red areas. Sherrod Brown, a stalwart champion of unions who has made fighting for “the dignity of work” his signature issue, has been elected three times to the U.S. Senate in increasingly Republican-friendly Ohio. So has Montana’s Jon Tester, who has proposed a bill to bar corporations that lock out their employees during labor conflicts from receiving tax breaks, deductions, or credits.In his two runs for the White House, Bernie Sanders articulated a similar message with a blunt passion no other politician with national standing could match. But his identity as a proud Socialist may have cost him the nomination by turning off the strong partisans who vote in Democratic primaries.The Democrat who did get elected president could take some actions that would help stoke a movement of working people. Mr. Biden could speak often and forcefully about how Build Back Better would improve the lives of most Americans. He could stress the virtues of the Protect the Right to Organize Act, which passed the House a year ago, but remains stalled in the Senate by the seemingly unbreakable filibuster. Right now, few people outside the Beltway bubble are likely to have even heard of this measure.Last fall, a liberal polling firm conducted a survey in swing states and battleground districts to test how voters would react to a Democratic candidate who articulated such an aggressive pro-worker, anti-corporate message:People are living paycheck to paycheck and struggling to pay their bills and taxes. They need a government that looks out for the middle class, working families, small businesses, and the vulnerable who work hard. They don’t need a government that jumps whenever the biggest corporations send money and lobbyists. My approach is blue collar. We should bend over backwards for those who work hard so we create jobs in America and grow the middle class again.After hearing that pitch, respondents increased their backing for Democrats to eight percentage points from three, enough to win seats in nearly every battleground district and state. Bruised by the hardships of the long pandemic, many of those polled, according to the longtime strategist Stanley B. Greenberg, were “surprised to hear that Democrats are dissatisfied with an economy where many of the voters … live paycheck to paycheck” and that “Democrats prioritize big changes in the economy and who holds power.”