Harvard University Law Professor Alan Dershowitz is no conservative. A prominent supporter of President Barack Obama, Dershowitz lobbied Jewish voters to back the president in both of his campaigns. But the famous attorney’s heterodoxy on some matters dear to liberal hearts, like George Zimmerman’s presumed guilt, have increasingly put him on the outs with his fellow Democrats. It seems that congressional Democrats’ petty determination to boycott Israeli Prime Minister Benjamin Netanyahu’s speech to Congress in a display of fealty to Obama might have sent the law professor over the edge.

“Congress has every right to invite, even over the president’s strong objection, any world leader or international expert who can assist its members in formulating appropriate responses to the current deal being considered with Iran regarding its nuclear-weapons program,” Dershowitz wrote in an op-ed published in The Wall Street Journal. “Indeed, it is the responsibility of every member of Congress to listen to Prime Minister Netanyahu, who probably knows more about this issue than any world leader, because it threatens the very existence of the nation state of the Jewish people.”

Beyond defending the Congress’s authority as a co-equal branch and its role in setting American foreign policy, Dershowitz went on to lament the Democratic impulse to isolate and alienate liberals who also support Israel’s right to robustly defend its national interests.

Another reason members of Congress should not boycott Mr. Netanyahu’s speech is that support for Israel has always been a bipartisan issue. The decision by some members to boycott Israel’s prime minister endangers this bipartisan support. This will not only hurt Israel but will also endanger support for Democrats among pro-Israel voters. I certainly would never vote for or support a member of Congress who walked out on Israel’s prime minister.

One should walk out on tyrants, bigots and radical extremists, as the United States did when Iran’s Mahmoud Ahmadinejad denied the Holocaust and called for Israel’s destruction at the United Nations. To use such an extreme tactic against our closest ally, and the Middle East’s only vibrant democracy, is not only to insult Israel’s prime minister but to put Israel in a category in which it does not belong.

So let members of Congress who disagree with the prime minister’s decision to accept Speaker Boehner’s invitation express that disagreement privately and even publicly, but let them not walk out on a speech from which they may learn a great deal and which may help them prevent the president from making a disastrous foreign-policy mistake. Inviting a prime minister of an ally to educate Congress about a pressing foreign-policy decision is in the highest tradition of our democratic system of separation of powers and checks and balances.

Dershowitz’s call to action is a timely one. Increasingly, being a Democrat means embracing hostility or indifference toward Israel’s approach to safeguarding its national security – a position that is dramatically out of step with the rest of the nation.

According to Gallup polling released this week, 70 percent of Americans continue to view the Jewish state “very” or “mostly favorably.”

“In fact, Israel’s public image in the U.S. has been fairly strong since 2005, with an average 68% of Americans viewing it favorably,” Gallup’s Lydia Saad observed.

But Israel’s favorability is inflated by the fact that over eight in 10 Republicans, and nearly six in 10 independents, view Israel more positively than they do the Palestinian authorities. Fewer than half of Democrats say the same, and those Democrats who do support Israelis over the Palestinians are declining in number.

Dershowitz’s position is an increasingly untenable one for today’s Democratic Party. That fact is perhaps best demonstrated by moderate Democratic Sen. Tim Kaine’s (D-VA) announcement today to join with the boycotters.

“A number of respected Israeli national security and political leaders have criticized the address as improperly mixing American foreign policy with Israeli domestic politics,” Kaine said in a statement. “Creating such an impression is not only disrespectful to the Israeli electorate, it also undermines the institutional values that Congress should uphold.”

But while the president is massaging his wounded ego and demanding his fellow Democrats join him in a display of contempt for the Israeli leader, Netanyahu has accused the Western powers of tacitly accepting the fact that Iran will one day go nuclear. According to reporting, Saudi Arabia is seeking back channels in which they will reportedly float an offer to facilitate an Israeli attack on Iran’s nuclear facilities in exchange for progress in the peace process. Is a regional war in the Middle East a fair price to pay to satisfy the president’s demand for satisfaction amid perceived insults from Israel’s leader? Democrats apparently seem to think it is.