Like the tea-party stirrings among Republicans in 2009, Bernie Sanders is a sign that liberal activists are looking for a fight. Organized labor is threatening to challenge vulnerable moderate Democrats in primaries if they vote for the president’s fast-track trade authority. The newly-aggressive grassroots are letting their ideology blind them to political realities. Since left extremists like Ralph Nader (even with Michael Moore’s backing) never pull more than about 3% of the vote, and all they’ve accomplished is the election of George Bush II, it looks like Clinton and the Democrats may be doomed in 2016 as Gore was in 2000.

The full article is here in the National Journal.

Make no mistake: Sanders is not a “liberal purist,” as The New York Times referred to him in its Burlington dispatch—he’s further left than that. He’s never even been a Democrat. But among the most liberal Democrats, he polled at 28 percent, with Biden trailing him by 24 points in a hypothetical matchup.

The closest recent parallel to Sanders is Dennis Kucinich, who tallied less than 4 percent of the total primary vote in 2004. Ralph Nader’s high-water mark was in 2000, when his 2.7 percent third-party tally was nonetheless enough to spoil Al Gore’s hopes for the presidency.

It’s no coincidence that Hillary Clinton has tacked left on every issue of consequence, even though she doesn’t need to worry about winning the Democratic presidential nomination. In the past year, she’s backtracked on supporting free trade deals, run to President Obama’s left on immigration, and offered no support to her party’s hawks in skeptically viewing the possible nuclear deal with Iran. On all these issues, she’s risking general-election support catering to a constituency that doesn’t seem all that threatening. Far from running on the warm memories of her husband’s presidency, she’s implicitly rebuking much of his legacy.

This is the real threat that Sanders poses to Clinton—not as a candidate, but as a sign that the Democrats’ version of the tea party is ascendant at the worst possible time. Sanders is a weak challenger; he’s got an unhealthy mix of Donald Trump’s ego and Michele Bachmann’s bombast. He’s won statewide office in Vermont, the most liberal state in the country, with a population smaller than Bachmann’s old congressional district.

But Sanders is poised to play the same role as Mitt Romney’s 2012 GOP tormentors, a motley cast of characters who stood no chance of winning the nomination but gradually pushed Romney to the right. After all, Romney’s infamous line about “self-deportation” was a reaction to the fear that he was vulnerable on his right flank from the likes of Rick Santorum and Newt Gingrich.

For all their differences, Clinton has a political tin ear similar to Romney’s, and she is already worried about shoring up her left flank at the possible expense of essential support from the political center. But she’s clearly spooked by the notion that a sizable chunk of her party is a lot closer to his views than she would have imagined when she was last in the White House.