Webb is easily the most conservative Democrat in the 2016 field: The former Reagan Secretary of the Navy won his seat in Virginia based on pragmatic opposition to Bush-era foreign policy than the populist fever that has swept the American left in recent years. In the hours since the close of the debate, progressives have heaped scorn on what they viewed as Webb’s foreign-policy bellicosity, his critique of affirmative action, and for throwing cold water on Bernie Sanders’ plans for new taxes and spending. After Sanders called for, “a political revolution,” in which “millions of people begin to come together and stand up and say, “Our government is going to work for all of us, not just a handful of billionaires,” Webb demurred. The Senator said:

I got a great deal of admiration and affection for Senator Sanders, but I—Bernie, I don’t think the revolution’s going to come. And I don’t think the Congress is going to pay for a lot of this stuff.

In Republican or Democratic primary debates, candidates don’t usually get credit for telling the truth. While the Republican party has suddenly forgotten its obsession with deficits over the past six years and fallen over themselves to propose unrealistic tax cuts that would explode the deficit, Democrats, and Bernie Sanders in particular, have been trumpeting spending plans while forgetting about the huge majorities that the Republican Party now enjoys in Congress.

The Wall Street Journal recently published an analysis of Bernie Sanders’ spending proposals, arguing that he’s calling for $18 trillion in new spending. In reality, the majority of this new spending would come from the candidate’s plan to turn American healthcare into a single-payer Medicare-for-all model. Since there’s serious debate over whether this is a workable solution, or whether it would actually amount to new spending rather than a change in who’s spending the money, let’s set that aside for a moment. Sanders’ plans still calls for $3 trillion in new spending over 10 years. This would require higher payroll taxes, higher corporate taxes, higher taxes on wealthy workers’ income and capital gains, as well as a brand new financial transaction tax if these proposals aren’t to vastly increase the deficit.

As former advisor to President Obama Austen Goolsbee told the Journal, even getting through less ambitious tax increases as part of Obamacare legislation was difficult back when there were huge Democratic majorities in Congress between 2008 and 2010. “Much, much more modest actions than those Bernie Sanders is describing were extremely heavy lifts, and many thought impossible,” he said. “Both of them came down to a single vote.”

It’s highly unlikely that a Democratic president will have a majority in Congress starting in 2017. The combination of gerrymandering in the wake of the 2010 Republican sweep of state governments and the Republican party’s more even distribution of support across Congressional districts means that its House majority is likely safe until at least 2021. If a Democrat is elected president next fall, he (or she) will be in the same position that Obama is today: forced to compromise with Republicans or to act via executive order.

More importantly, the new president will face a problem Obama hasn’t had to deal with quite some time: a rising deficit. By 2025, the Congressional Budget Office doesn’t just see the deficit rising in dollar terms, but also as a percentage of the economy. If current trends continue, the deficit will be 3.7% of GDP, much faster than projected economic growth. And even if you don’t believe that federal government debt isn’t a huge problem right now, a continually rising debt relative to the size of the economy isn’t sustainable. The next president will have to deal with this, likely in a bipartisan fashion. And that’s one matter you haven’t heard a lot about on any debate stage these days.