US democracy faces a momentous threat, says Joe Biden – but is he up for the fight?

The president's speech in Philadelphia decried Republicans' assault on voting rights but critics say it offered few answers, especially on Senate rules that let the minority to block reform

Few in the audience applauding Joe Biden could have questioned the sincerity of his warning about a momentous threat to American democracy.

But they may have walked away with lingering doubts about his ability to meet the moment or answer fears that even the office of the presidency will be found politically impotent in the face of the challenge.