DEMS IN CONFLICT: A more agitated Sanders tries to fend off attacks of nervous establishment.

Democratic presidential hopeful Bernie Sanders pulled up to a supporter’s garage in his hulking campaign bus, prepared to give a pep talk to a few dozen devotees who had been tirelessly knocking on doors for him in the final days before the Iowa caucuses.

But first he had something to get off his chest. Visibly agitated, Sanders teed off on a television ad being aired by his chief rival, Hillary Clinton, implying he’s on the wrong side of two key issues: gun control and women’s reproductive rights. . . .

With an Iowa win on Monday within reach, Sanders is suddenly running a gantlet of criticism from Clinton and her allies, many in the media and even President Obama, all of whom seem to have awakened to the looming reality that a 74-year-old self-described democratic socialist could, at the very least, damage the Democratic front-runner and turn her march to the party’s nomination into a long, costly slog. . . .

In recent days, he has fielded questions about whether his health plan is too fanciful, whether someone tagged with the “socialist” label can win a general election, whether someone of his age is fit to serve, whether he’s been a strong enough champion for women and whether he’s the person to protect Obama’s legacy.

All of it has pushed Sanders into a defensive, and political, crouch.

Then there’s the whole manufactured “BernieBro” issue.