Israeli Prime Minister Benjamin Netanyahu walks with House Speaker John Boehner in May 2011. Boehner’s invitation to Netanyahu is straining relations between Israel and the United States. (Evan Vucci/AP)

The Israeli prime minister’s surprising announcement that he will address a joint meeting of Congress in early March is straining relations between Israel and its closest ally.

House Speaker John A. Boehner invited the Israeli leader to speak to Congress amid a heated debate over whether new sanctions, to be imposed if talks fail, would scuttle tenuous negotiations with Iran over its nuclear program.

The White House on Thursday said that President Obama would not meet in Washington with Prime Minister Benjamin Netanyahu, who is in the midst of an election campaign. “We want to avoid even the appearance of any kind interference with a democratic election,” said White House spokesman Josh Earnest.

Netanyahu is expected to offer up a harder-line view, supported by many Republicans and some Democrats, that the threat of more sanctions is needed to blunt Iran’s ambitions to build a nuclear weapon.

Such a move, Obama has said, would cause the delicate talks with Iran to fail and increase the likelihood of armed conflict.

President Obama will not meet with Benjamin Netanyahu when the Israeli prime minister visits the U.S. in March as the invited guest of Republican congressional leaders. (Reuters)

Neither Boehner nor Netanyahu gave the administration any notice of his planned visit, and on Thursday, some U.S. officials were warning that the breach of traditional diplomatic protocol could have lasting consequences for the Israeli leader.

Secretary of State John F. Kerry has made nearly 50 calls in the past month to world leaders on issues such issues as the U.N. Security Council Resolution on Palestine and a probe by the International Criminal Court.

“The bilateral relationship is unshakable,” said a source close to Kerry. “But playing politics with that relationship could blunt Secretary Kerry’s enthusiasm for being Israel’s primary defender.”

Kerry met for more than two hours on Tuesday with Israel’s ambassador to the United States, who never mentioned the invitation from Boehner or the prospect of a Netanyahu visit this spring. “The secretary’s patience is not infinite,” said the source close to Kerry, who was granted anonymity to speak frankly about the strained relations caused by the visit.

The debate over the sanctions has already provoked a rare intervention from British Prime Minister David Cameron, who last week lobbied U.S. lawmakers to forgo any new punitive measures against Tehran. Over the weekend, the head of Israeli intelligence also discussed the impact of new sanctions with a delegation of visiting U.S. senators.

Exactly what Mossad chief Tamir Pardo said to the visiting American delegation was a subject of yet more argument on Thursday.

Kerry told reporters on Wednesday that the Israeli intelligence chief had made an impassioned case against new sanctions, saying that they would be akin to “throwing a grenade into the process.” Such a position would have put him at odds with his prime minister.

Pardo, meanwhile, denied saying any such thing during a Jan. 19 meeting with the Americans. Instead, the Mossad director said he reiterated that “firm pressure” was needed “to bring about meaningful compromises from the Iranian side.”

“Despite what was reported, the head of the Mossad did not say he opposes additional sanctions against Iran,” said a Mossad statement issued through the prime minister’s office. “The head of the Mossad emphasized in the meeting the extraordinary effectiveness of the sanctions against Iran, for a number of years, in bringing Iran to the negotiating table.”