Today, Israeli Prime Minister Benjamin Netanyahu will give a speech to a joint session of Congress, on invitation from House Speaker John Boehner. It is virtually certain he will argue that the Obama administration's ongoing negotiations with the Iranian government should be scrapped, and that more sanctions should be heaped on Iran, to prevent the theocratic regime from developing a nuclear weapon.

But there's more at work here than deterring Iran. Netanyahu is angling to win the upcoming Israeli general election, set for March 17th. If he can dynamite a potential Iran-U.S. rapprochement, demonstrating his boldness and mastery of U.S. politics, he very well might sweep to victory.

Giving Netanyahu this chance is wrong. He has been consistently dishonest about the purported Iranian threat, and conspiring with him to undermine a worthy diplomatic effort is grossly irresponsible.

When it comes to Iran and its nuclear program, Netanyahu is simply not a credible source. On no less than five separate occasions since 1992, he has warned that Iran was imminently within reach of a nuclear bomb, warnings that he has used to argue for a preemptive American strike. Each time his projected window ran out, he simply moved the date forward a couple years. Like the Friedman Unit during the Iraq War, Netanyahu has claimed that Iran is between one and seven years away from a nuclear weapon — for the past 23 years running.

Most recently, he predicted before the U.N. General Assembly (complete with a bizarre Wile E. Coyote-style bomb diagram) that Iran would have a nuke by the summer of 2013 at the latest. But Al Jazeera recently reported that this assertion was completely at odds with the contemporaneous opinion of Mossad, Israel's foreign intelligence service.

It's worth noting that Netanyahu did the exact same song and dance before the Iraq War, too, testifying before Congress that "there is no question whatsoever" that Saddam Hussein was working on nuclear weapons and that he would thus pose an existential threat to Israel and world security.

In other words, the historical record shows that Netanyahu is not just an evidence-proof, anti-Iran zealot trying to foment war between that nation and the U.S., but also that he will actively lie about what he knows.

Even if he were a straight shooter, his strategic vision of Iran is ridiculous. Before AIPAC this week, he argued that Iran is a martyr state, that it seeks a nuclear bomb to immediately use against Israel. If so, then why didn't Iran develop a bomb years ago? Remember that Iran is several times wealthier than North Korea, which managed a successful nuclear bomb despite almost total international isolation.

Then there's the problem that Netanyahu's assertion is at odds with all available evidence. On the contrary, all indications are that Iran is an average authoritarian nation. No true fanatic state would help American forces fight ISIS in Tikrit. Many in Israel's military establishment disagree with Netanyahu's assessment, which is why 180 retired Israeli generals and security officers urged Netanyahu to cancel his speech, arguing that it would damage the U.S.-Israel relationship and accelerate the Iranian nuclear program.

Indeed, Netanyahu's position makes his preference for more sanctions doubly illogical. As JJ Goldberg points out: "Apparently [Iran is] irrational enough to welcome nuclear Armageddon, but rational enough to yield to economic punishment."

It would be hard to imagine someone less helpful to be air-dropped into the middle of sensitive negotiations. It's also more than a little rich for conservatives to be so openly trying to undermine a U.S. diplomatic initiative. If the tables were turned, bug-eyed reactionaries would be screaming about anti-American communist Demoncrats who may well mount a fifth column. As Jonathan Chait jokes:

[Conservatives] are defending the right of a foreign leader to interfere with American foreign policy in a way that would be unimaginable if, say, congressional Democrats had invited the French president to argue in 2003 against the Iraq War. Here conservatives are embracing a cosmopolitanism so broad they feel unembarrassed at conspiring with a foreign country to undermine their own country’s negotiations. [New York]

However, Netanyahu is also taking an awful risk here. Israel's support from the United States has long been based on adamantine bipartisan agreement. As Greg Sargent documents, blatantly trying to undermine a U.S. president, after Netanyahu all but declared his support for Mitt Romney in 2012, risks turning Israel into a Republicans-only issue. If that happens, it will be clear who is to blame.