Former Vice President Joe Biden blasted President Trump's decision to kill Iranian Maj. Gen. Qassem Soleimani as the latest in a series of "dangerously incompetent" steps taken by Trump.

In a speech Tuesday, Biden, who's seeking the Democratic presidential nomination, tied the deadly U.S. drone strike directly to Trump's decision to walk away from the nuclear agreement the Obama administration and other nations struck with Iran in 2015.

"This was avoidable," Biden said. "The seeds of these dangers were planted by Donald Trump himself on May 8, 2018 — the day he tore up the Iran nuclear deal, against the advice of his own top national security advisers."

Trump has called the nuclear pact a "horrible, one-sided deal."

The speech, delivered in New York City, where Biden was also raising money Tuesday, is the former vice president's latest attempt to focus on Trump's decision to kill Soleimani. While other Democratic candidates have criticized the move as a dangerous escalation in a volatile region, Biden has returned to it again and again while campaigning in Iowa and elsewhere.

Biden has long framed himself as the Democratic candidate best-positioned to repair the international relationships his party believes the Trump administration has frayed. Biden spent years on the Senate Foreign Relations Committee before serving as an international point main during his eight years as Barack Obama's vice president.

Biden has said the Soleimani killing — and Trump's behavior in its wake — are prime examples of the spur-of-the-moment decision-making he says is damaging the United States' national security and standing in the world.

The Trump administration has said that Soleimani was planning an imminent attack on the U.S., but on Tuesday, Biden criticized what he said have been Trump's limited explanations for the strike in the days since it was carried out.

"We have not heard a sober-minded explanation to reassure the American people," Biden said. "No press conference, or consultation with our Congress. No, what we've heard so far from this president are tweets, threats and tantrums."

Later, Biden spoke directly to Trump: "You have to speak directly to the American people. That's your job, as president."

A return to the negotiating table with Iran has been a centerpiece of the Biden campaign's foreign policy vision. After the Soleimani killing, Iran has said it won't honor its commitments to limit its enrichment of uranium — a key component of the nuclear pact.

Biden, who did not take questions after the 20-minute speech, did not directly say whether he thinks the nuclear deal is still salvageable. But he indicated that if Iran shifts gears, it could be.

"The only way out of this crisis is diplomacy," Biden said.

This summer, after Iran had already exceeded the agreement's uranium-enrichment levels, Biden said he still believed the deal could hold. "If Tehran returns to compliance with the deal, I would rejoin the agreement and work with our allies to strengthen and extend it, while more effectively pushing back against Iran's destabilizing activities," he said during a July foreign policy speech.

While Biden has framed his potential administration as a mission to undo Trump's foreign policy legacy, he conceded Tuesday that the task would be difficult.

"We're in a much worse position to meet the demands of this crisis than we were when President Obama and I left office," Biden said.

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