But in a sign the United States is still reluctant to embroil itself in another Mideast military effort, Biden cautioned more than 13,000 Israel supporters at the American Israel Public Affairs Committee's annual conference that if Israel or the United States acts too hastily, without exhausting every other reasonable option, they could risk losing the backing of the international community.
"That matters because God forbid we have to act, it's important that the rest of the world is with us," Biden said to muted applause.
Israeli Prime Minister Benjamin Netanyahu, speaking to the conference by video link from Jerusalem, pushed back against such reluctance, reflecting the tension still present between the United States and its closest Mideast ally as they seek a united front to stave off Iran's nuclear program.
"From the bottom of my heart and from the clarity of my brain, words alone will not stop Iran. Sanctions alone will not stop Iran," Netanyahu said.
The United States and world nations have imposed crippling sanctions on Iran's oil and financial industries in hopes of forcing Tehran back to the negotiating table and persuading it to give up nuclear ambitions.
Netanyahu has warned that the world has until this summer - at the latest - to keep Iran from building a bomb, and has repeatedly hinted at Israel's willingness to launch a military strike to stop it, an endeavor the United States likely would be dragged into.
Participants in the conference were struck by Netanyahu's tough talk, which suggested that military action was inevitable.
"I'm afraid there is going to be something drastic that could happen," said Barbara Rogan, a retired librarian from Westport, Conn. "Iran feels, I think, that they have nothing to lose while forging ahead. The sanctions aren't enough to frighten them."