Three of four Republican presidential candidates called for the US to up its rhetoric against Iran, Wednesday night, saying current President Barack Obama had not done enough to stop Tehran’s nuclear program.

Only isolationist candidate Ron Paul refrained from calling for the US to openly threaten a strike on Iran during the debate in Arizona. Newt Gingrich, Mitt Romney and Rick Santorum all said the White House had stumbled in publicly breaking with Israel on the issue.

“I do believe there are moments to preempt,” said ex-House Speaker Newt Gingrich. “You have an absolute moral obligation to defend the lives of your people by eliminating the capacity to get nuclear weapons.”

Gingrich also slammed Joint Chiefs of Staff head Gen. Martin Dempsey for calling Iran a rational actor in a recent interview.

The four were responding to a question by moderator John King about whether they would have sided with the Obama administration or Jerusalem on the question of how best to deal with Iran. The White House has called for sanctions against Tehran to be given a chance to work, while foreign reports seem to point to an increasing willingness by Israel to knock out Iran’s nuclear program before it becomes operational.

Several administration officials have met with or spoken to Israeli officials recently, reportedly in an attempt to talk them down from an attack on Iran. US Director of National Intelligence James Clapper is due in Jerusalem Thursday for the same reason.

In the debate, Romney called the Iran issue Obama’s biggest failure, saying the president should make sure Tehran knows the military option is on the table. He added that the sanctions against the ruling regime of President Mahmoud Ahmadinejad were inadequate.

“This president should have put in crippling sanctions against Iran. He did not,” said Romney.

Santorum echoed his calls for a visible display, if not use, of force.

The debate, likely the last before the Republicans settle on a candidate to challenge Obama for the White House, focused mainly on domestic issues.