There’s plenty going on in the Trump campaign to keep voters’ attention on the growing split in the Republican party. But there are also signs of serious divisions in the Democratic party, and I’m not just referring to the tensions between the Sanders and Clinton camps, although these certainly could dampen voter turnout in November.

Even as the Democrats struggle to find a way to bring progressives and centrists together, a fault line has emerged in the labor movement between the building trade unions and the AFL-CIO. As the Washington Post reported last month, the building trade unions attacked a new labor partnership led by the AFL-CIO with billionaire environmentalist Tom Steyer, whose opposition to the Keystone XL Pipeline upset unions that viewed the project as an important source of new construction jobs.

The primary source of the conflict is a new super PAC called For Our Future that Steyer, a former hedge fund manager, is establishing in conjunction with the AFL-CIO; the American Federation of State, County and Municipal Employees (AFSCME); the American Federation of Teachers (AFT); and the National Education Association (NEA).

The PAC, according to a spokesperson for Steyer, will provide an important vehicle to “help elect progressive leaders who are committed to a just transition to a clean energy economy.”

The fixation of the building trade unions on fossil fuel energy in general and the Keystone XL pipeline in particular overlooks the jobs potential of building the clean energy infrastructure necessary to avoid runaway global warming. Furthermore, there is a pressing need to rebuild our country’s civil infrastructure, including roads, bridges, water systems, and schools, And what about making our cities climate resilient, especially along the coasts? An enormous number of construction jobs would be generated, and none of this even involves what a transition to clean energy would generate in the way of new job opportunities.

In addition, federal borrowing rates are at historic lows (near zero) and the federal deficit has declined dramatically since the early years of the Obama administration, so there’s really no excuse for the country not to be undertaking the kinds of public works projects that were so widespread in the 1930s.

The main difference between now and the 1930s, of course, is that the Republicans are in control of the House and Senate and they are dead set against the federal government borrowing the money necessary to fund these projects. They continually raise the alarm about the federal debt to GDP ratio even though there is no real consensus about what constitutes a “safe zone.” See here for more details. We could take a lesson from the Chinese government, which doesn’t even put infrastructure spending in the deficit total because they consider it to be an asset, not a liability.

At any rate, there are plenty of construction jobs to be had with the right national policies in place, many more than will be lost if we stop building pipelines and fossil fuel power plants. In order for this happen, of course, the different wings of the labor movement have to get on the same page. There’s no getting around that fact; if it doesn’t happen, the political consequences will be dire. It’s clearly another reason why the 2016 elections will mark a critical turning point in the nation’s path to the future.