I served in the United States Senate for thirty-six years. I believe deeply in its traditions, in its value as an institution, and in its indispensable constitutional role in the conduct of our foreign policy. The letter sent on March 9th by forty-seven Republican Senators to the Islamic Republic of Iran, expressly designed to undercut a sitting President in the midst of sensitive international negotiations, is beneath the dignity of an institution I revere.

This letter, in the guise of a constitutional lesson, ignores two centuries of precedent and threatens to undermine the ability of any future American President, whether Democrat or Republican, to negotiate with other nations on behalf of the United States. Honorable people can disagree over policy. But this is no way to make America safer or stronger.

Around the world, America’s influence depends on its ability to honor its commitments. Some of these are made in international agreements approved by Congress. However, as the authors of this letter must know, the vast majority of our international commitments take effect without Congressional approval.

Biden’s unyielding pursuit of “engagement” with Iran for more than a decade has made it easier for Tehran to pursue its nuclear program, while his partisan obsession with thwarting the Bush administration has led him to oppose tough sanctions against hard-liners in the Iranian Revolutionary Guard.

Not long after President Bush declared Iran part of an “axis of evil,” Biden headlined a March 13, 2002, dinner at the American Iranian Council, an organization underwritten at the time by a dozen oil companies and dedicated to ending sanctions on Iran…

Kaveh Mohseni, a spokesman for the Student Movement Coordination Committee for Democracy in Iran, calls Biden “a great friend of the mullahs.” He notes that Biden’s election campaigns “have been financed by Islamic charities of the Iranian regime based in California and by the Silicon Iran network,” a loosely-knit group of wealthy Iranian-American businessmen and women seeking to end the U.S. trade embargo on Iran.

“Biden has been too cozy with the supporters of the Iranian regime, which is anti-American, anti-Iranian, and has a horrendous human rights record,” said Sardar Haddad, an Iranian pro-democracy activist based in Texas.

Biden told Boston Globe columnist H.D.S. Greenway in 2005 that the United States should address Iran’s “emotional needs” and conclude a “nonaggression pact” with the Tehran regime.

The November 2007 National Intelligence Estimate affirmed the fruits of such investment when it found that Iran had pursued a nuclear weapons program until 2003. Although Biden’s embrace of engagement coincided with Iran’s nuclear warhead work, he acknowledged no error. He told reporters on Dec. 4 that Bush had “misrepresented” the intelligence in a drive to war and declared the same day, “You cannot trust this president.”

In early 2007, evidence mounted that the Iranian Revolutionary Guard Corps was planning terrorist activities in Iraq. An August 2007 National Intelligence Estimate found that “Iran has been intensifying aspects of its lethal support for select groups of Iraqi Shia militants” and that “Explosively formed penetrator (EFP) attacks have risen dramatically.” The next month, the Senate considered a bipartisan amendment to designate the Revolutionary Guard Corps as a terrorist organization, an important step to aid nonviolent efforts to deny it funds and financing. Biden was one of only 22 senators to vote against it. “I voted against the amendment to designate Iran’s Revolutionary Guard as a terrorist organization because I don’t trust this administration,” he said.

Secretary of State Condoleezza Rice explained the administration’s position on Mr. Assad to the Senate Committee on Foreign Relations in 2007.

“If there were any evidence, any hint, that Syria was changing its course — and it should just change its course — we don’t have an ideological problem with talking to Syria,” Ms. Rice testified. “We’ve talked with them under this administration. We could do it again.

“But the problem is, they are not engaging in constructive behavior. And we don’t see how that would change, currently, by talking to them.”

Mr. Biden, then the committee’s chairman, scolded her and reminded her of her duties.

“I do not agree with your statement, Madame Secretary, that negotiations with Iran and Syria would be extortion, nor did most of the witnesses we heard in this committee during the last month,” Mr. Biden said. “The proper term, I believe and they believe, is diplomacy, which is not about paying a price but finding a way to protect our interests without engaging in military conflict. It is, I might add, the fundamental responsibility of the Department of State, to engage in such diplomacy, as you well know.”

Presidential hopeful Delaware Sen. Joe Biden stated unequivocally that he will move to impeach President Bush if he bombs Iran without first gaining congressional approval.

“The president has no authority to unilaterally attack Iran, and if he does, as Foreign Relations Committee chairman, I will move to impeach,” said Biden.