Paul Begala, a Democratic strategist and CNN political commentator, was a political consultant for Bill Clinton's presidential campaign in 1992 and was counselor to Clinton in the White House. The opinions expressed in this commentary are his. View more opinion articles on CNN.

(CNN) Donald Trump is probably dancing his svelte, 243-pound self around the White House about now. News that Sen. Sherrod Brown (D-Ohio) is not running for president is no doubt turning Trump's "Executive Time" into party time.

(I'll pause for a moment while you deal with the thought of our President doing the Dougie . Better? OK.)

Mr. Trump surely could use some good news. His former lawyer and fixer, Michael Cohen, has implicated Trump in alleged felonious conduct. His summit with his dear friend, the Dear Leader Kim Jong Un, exploded like a Musudan missile. The trade deficit Trump promised to reduce is instead at a record high . And he faces investigations by, among others, Congress, special counsel Robert Mueller, the Southern District of New York, the attorney general of New York, the Washington, DC attorney general, and Hawaii Five-0. (I made up one of those.)

Politically, these are not the best of times for Mr. Trump, either. The latest NBC News/Wall Street Journal poll shows an uptick in his approval, actually. But he's still at an anemic 46%. More troubling for him, only four in 10 Americans plan to vote for him for re-election, while 48% say they plan on voting for a Democrat for president.

Here's why Mr. Trump is doing the Humpty Dance on the Truman Balcony: Sherrod Brown could have beaten him, and I bet Trump knows it.

Why? The math is simple. Trump got 46% in 2016. He has not been over 50% in the national polls for a single day as president. Brown, a Midwestern economic populist, would have eaten into Trump's working-class support -- a loss Trump could not offset by gaining ground among, say, people of color, or younger voters.

To be clear: I have no preference in the 2020 Democratic presidential contest. For the first time in my life I am actually an undecided Democrat. But I have my eyes on the prize, and the prize is sending Mr. Trump back to Fifth Avenue -- or perhaps an extended stay at Club Fed.

I'm a JFK Democrat: I will pay any price, bear any burden, support any friend, oppose any foe to ensure the defeat of Donald J. Trump.

The rumpled, gravelly voiced Brown seemed almost custom-made to puncture Trump's phony "blue collar billionaire" myth. Look at how the national media described him in headlines today (emphasis mine):

Midwestern populist Sherrod Brown decides against running for president" -- LA Times : "Sherrod Brown decides against running for president"

Wall Street critic Sen. Sherrod Brown will not challenge Trump in 2020." -- CNBC: Sen. Sherrod Brown will not challenge Trump in 2020."

Heartland Progressive Sherrod Brown won't run for president in 2020." -- New York magazine : "Sherrod Brown won't run for president in 2020."

With Trump in a cul-de-sac, unable to expand his appeal beyond working-class whites, a Democrat who could pry away some of those Trump voters looked like a winner to me. After all, Brown won a resounding re-election in November, winning his native Ohio by 6%. Hillary Clinton lost Ohio by 8% in 2016.

You don't need to be a math major to know that a 15-point improvement over Hillary's razor-thin losses in the Big Ten states of Pennsylvania, Wisconsin and Michigan means the moving vans would be rolling up to 1600 Pennsylvania Avenue.

While Brown won't be running, I hope Democrats pick up his message. "The Dignity of Work" is not just a slogan for Brown; it is the work of his life. Trump's re-election depends on Democrats practicing the politics of self-destruction -- and you can be sure that Donald Trump, Fox News and Russian intelligence will be doing all they can to divide Democrats.

The key, it seems to me, is to find issues that unite the Democrats' progressive base and welcome disaffected suburban Republicans, while appealing to working class voters who may feel betrayed by Trump. The path to that coalition lies in economic populism.

JUST WATCHED Sherrod Brown: Howard Schultz is an 'idiot' Replay More Videos ... MUST WATCH Sherrod Brown: Howard Schultz is an 'idiot' 01:07

To be clear, nothing in Brown's record is less than progressive on social issues. He voted against the anti-gay Defense of Marriage Act back in 1996 and has a perfect record from the Human Rights Campaign.

A Sherrod Brown candidacy would have tested the proposition that a strong social progressive could earn the support of disillusioned working-class Trump voters by answering Trump's wedge issues with what President Bill Clinton used to call "web issues" -- economic issues that unite working people of all identities.

Brown's decision opens up more room on the populist front. If former Vice President Joe Biden runs, he could fill that lane with his "Joe Lunchbucket" appeal. Sen. Bernie Sanders of Vermont has always had a particularly sharp focus on economic issues, as has Sen. Elizabeth Warren of Massachusetts.

Others may try to emulate Sherrod Brown's working-class heroism; I hope so.