Just a few years ago, Jim Webb was hailed as the Democratic Party’s great political hope: an ex-Republican and decorated Vietnam combat hero with centrist, independent views and refreshing candor who opposed the Iraq war.

Now he’s become the first Democratic casualty of the 2016 presidential race.

Yes, Webb ran a lackluster campaign. But the bigger problem, as he noted Tuesday, was that “my views on many issues are not compatible with the power structure and the nominating base of the Democratic Party.”

In other words, Democrats like Webb — or such fabled party figures as Pat Moynihan, Sam Nunn, Scoop Jackson and even John Kennedy — have no place in today’s party of isolationism and identity politics.

In 2008, recall, Hillary Clinton ran as the seasoned centrist alternative to Barack Obama. Today, she loudly proclaims her “progressive” credentials.

Indeed, today’s Democrats are far more comfortable with socialist Bernie Sanders than with Webb. So it’s not just a loser’s complaint when the Virginian laments the harshness of today’s political discourse and the way “our political candidates are being pulled to the extremes.”

Yet, if that pull is felt by both Democrats and Republicans, it’s the voters doing the pulling. And those voters have yet to revolt against harsh rhetoric — which is why outsiders are riding high in the polls.

Webb says he might run as an independent, but he’d be the longest of long shots. The sad fact is that, as Michael Barone writes, Jim Webb “speaks eloquently for a constituency that just doesn’t much exist anymore.”