The New York Times took an in-depth look at infrastructure yesterday — and the editors are bullish.

Part of the reason is politics.

Democratic presidential candidates usually favor more spending on infrastructure, appealing to their union base. But this year, the Republican candidate seems to agree. Clinton and Trump both advocate a massive infrastructure program to upgrade the nation’s physical bones, while also stimulating the economy.

By and large, economists think that’s a swell idea. America’s roads, bridges, tunnels and water systems are aging. They’ve absorbed a lot of wear and tear during the past century, when we rose from mid-size economic power to the largest in the world.

Across the country, there’s plenty of work that needs to get done—so much in fact that the American Society of Civil Engineers rated U.S. infrastructure a D+.

Economists also figure that with interest rates at historic lows, it’s better for the federal government to take on debt for this necessary work now than down the road, when rates could well be higher.

Sounds reasonable, right? With both Clinton and Trump on board, maybe it’ll happen whoever wins in November.

There’s just one problem with this kumbaya scenario: Republicans in Congress say, “Not so fast.” House Speaker Paul Ryan recently pointed out that a multi-year highway spending bill was passed last year, with bipartisan support. That’s enough, he says.

A major infrastructure push could boost the stocks of construction and engineering firms, heavy-equipment makers and steelmakers, among others. But with a cloudy outlook on Capitol Hill, it’s too early to act on campaign promises—even if they’re coming from both sides.

That said, America’s infrastructure problems aren’t going away. They’ll only get worse over time, and eventually Congress will have to cross this proverbial bridge when the real ones start collapsing. Globally, the need for modern infrastructure remains vast in fast-rising economies such as China and India, so as a long-term play, infrastructure makes sense.

We’re just not betting that Washington will act in 2017.