Sen. Bernie Sanders. (Charlie Neibergall/Associated Press)

The Washington Post editorial board published a scathing indictment of "Bernie Sanders's fiction-filled" presidential campaign Thursday morning. Here's the key paragraph:

Mr. Sanders tops off his narrative with a deus ex machina: He assures Democrats concerned about the political obstacles in the way of his agenda that he will lead a “political revolution” that will help him clear the capital of corruption and influence-peddling. This self-regarding analysis implies a national consensus favoring his agenda when there is none and ignores the many legitimate checks and balances in the political system that he cannot wish away.

Oomph. The Democratic candidate responded Thursday in Iowa by asking: "Where was The Washington Post to express concern that the middle class was shrinking?"

Let's start with what exactly Sanders has said on the subject of his ability to get things done as president. Here's what he said at a CNN-sponsored town hall event in Iowa on Monday night:

If we are serious about rebuilding the American middle class, if we are serious about providing paid family and medical leave to all of our people, if we are serious about ending the disgrace of having so many of our children live in poverty, the real way to do it is to have millions of Americans finally stand up and say, "Enough is enough," for people to get engaged in the political process, to finally demand that Washington represent all of us, not just a handful of very wealthy people.  

It's important to read between the lines of that response. Sanders is saying, in essence, that if he is elected, he will bring in lots and lots of liberal members of the House and Senate on his coattails — fundamentally altering the governing dynamic in this county for, at least, the past 15 years.

That the Republican majority in the House — the GOP's largest since World War II — and its five-seat Senate majority would simply be washed away by a Sanders tidal wave is, of course, possible. In the sense that it is possible that I, at age 39 and less than a year removed from ankle surgery, will dunk a basketball later today. But, possible is not probable — or even close.

Consider the latest handicapping of House races by the nonpartisan Cook Political Report. Write Charlie Cook and David Wasserman: "Today, the Cook Polit­ic­al Re­port counts just 33 seats out of 435 as com­pet­it­ive, in­clud­ing 27 held by Re­pub­lic­ans and six held by Demo­crats. That means that even if Democrats swept every single com­pet­it­ive seat, they would still fall three seats short of a ma­jor­ity."

Think about that for a minute. A clean sweep by Democrats of every competitive House race would still keep them in the minority. For the scenario that Sanders imagines to play out then, he would need to win by such a margin that he carries in with him candidates running in districts that the country's top political handicapper doesn't consider competitive. Again, possible. But not even close to probable.

The much more likely scenario that a President Sanders would face is, at best, a Congress divided between the two parties and very little appetite — even among Democrats — for the tax increases that he has acknowledged he would need to fund his programs.

That realpolitik argument is the one that Hillary Clinton has been making against Sanders for the past several weeks in Iowa and New Hampshire. At that same CNN town hall, Clinton insisted that "you have to have somebody who is a proven, proven fighter," adding: "Somebody who has taken them on and won and kept going, and will do that as president."

Although Clinton is almost certainly right, a message that embraces slow progress over wholesale change and experience in scoring points in a fight over trying to land a knockout blow is going to struggle in the context of a primary fight. As Clinton has.

But Clinton's struggles shouldn't take away from the fact that the political revolution that Sanders is promising to get his agenda done will almost certainly not happen, leaving him at the top of a still-fractured political system in Washington.