If you think, as I do, that Donald Trump could defeat Hillary Clinton this fall and become America's first certified autocrat, you need look no further for evidence than the recent Michigan Democratic primary.

To best understand why Hillary lost to Bernie Sanders, check out these exit poll stats: Blue-collar voters soundly rejected her, favoring Bernie by 14 percentage points. Meanwhile, 58 percent of all Democratic primary voters said free trade takes away American jobs; those voters soundly rejected her as well, favoring Bernie by 17 percentage points.

Ah yes, the trade issue.

Rust Belt states like Michigan, Ohio, and Wisconsin went blue in both Obama elections. But Michigan's primary reminds us that Hillary's standing with blue-collar voters is dangerously soft. Manufacturing jobs have steadily disappeared during the past quarter-century, and struggling workers pin the blame on free trade. Some experts agree with the workers; others do not. But Hillary's problem is that she's widely viewed as an establishment enabler of free trade - starting with her husband's championing of the North American Free Trade Agreement - and that's a political liability.

Bernie claims that NAFTA "cost us 800,000 jobs," including tens of thousands of jobs in the Midwest. His numbers may be wrong, at least according to a 2015 report by the nonpartisan Congressional Research Service that says NAFTA's adverse impact has been "modest." But the point is, blue-collar Rust Belters believe in their gut that free trade is the enemy. And in the Michigan Democratic primary, they voted accordingly.

And if they paid close attention to the Michigan debate, they may well have noticed Hillary's slippery explanation of her switcheroo on the Trans-Pacific Partnership trade deal. She praised it for years when the deal was in the works, but last fall she said she was against it.

She also spoke against it during the Michigan debate - and prompted Bernie to craft a tart response: "I am very glad that Secretary Clinton discovered religion on this issue. ... I was one of the first - not one of the last - to be in opposition to the TPP."

With respect to blue-collar voters, Bernie is not Hillary's biggest problem. She remains comfortably ahead in the national delegate count - she basically split Michigan's delegates with Bernie and widened her overall lead by slaughtering Bernie in Mississippi. Unless she's humbled Tuesday in Ohio and Illinois, she'll remain the heavy favorite. Which means that her biggest problem will likely be Trump.

Trump strengthened his claim on the Republican crown with three more wins, and he predicted he would win Rust Belt states in November. I don't dispute that possibility. Unlike Hillary, he rails against the "stupid" trade deals. Unlike Hillary, he doesn't have a track record of supporting trade deals. He's a master of staying on offense, and he can make Hillary play defense on those trade deals. If he can exploit her softness with working-class voters and win some Rust Belt states, he can redraw the Electoral College map that has lately favored the Democrats.

One other factor working against Hillary is that cable news networks shamelessly sucked up to Trump last week. For nearly 50 minutes following Tuesday's Republican primary, they carried every worthless word that fell from Der Leader's lips.

Back in the era when Fidel Castro was full of beans, he'd rail for uninterrupted hours on Cuban TV - and what we saw Tuesday night was Fidel on QVC. There he was, hawking Trump steaks, Trump magazines, Trump wineries, Trump golf courses, Trump University (which doesn't exist), and yet the cable networks refused to cut away ... to Hillary, for instance. She was speaking live in Ohio, previewing an autumn agenda. Regardless of whether you agree with her - on trade or anything else - at least she was talking policy.

But, according to what passes for cable news judgement, narcissism trumps substance. Welcome to the next eight months.

Dick Polman is the national political columnist at NewsWorks/WHYY in Philadelphia. Send email to dickpolman7@gmail.com.