The political slap fight over Israeli Prime Minister Benjamin Netanyahu's recent address to Congress was an embarrassment. But it was far from pointless. It reflected the fundamental divide between liberals and conservatives on Middle East policy.

When leaders of democracies visit the United States, they should be received with respect. That doesn't preclude vigorous, private disagreement, but churlish public behavior reflects badly on us all. If our politicians can't say something nice, they shouldn't say anything at all.

This White House didn't meet that minimal standard. Indeed, it's never been able to hide its disdain for Netanyahu. Last fall, someone in the administration sank to calling him names, as if Netanyahu's concerns about Iran's nuclear program were a symptom of a mental disorder, not a reflection of worries the Obama administration has said it shares.

But that's the problem: the administration appears way more concerned with making a deal with Iran than with verifiably ending Iran's nuclear program. As foreshadowed, the deal would be term limited, would allow Iran to keep thousands of centrifuges, and would not touch Iran's intercontinental ballistic missile program, which exists only to deliver a nuke.

That falls well short of ensuring that Iran's program is "exclusively peaceful," as the U.N. Security Council demanded in 2006. The Obama administration, which came into office pledging to support the U.N., is now eagerly trying to undercut it.

What's at issue here is a dispute over U.S. policy toward the Middle East that goes beyond Iran. It certainly goes beyond the tiresome argument that Speaker of the House John Boehner was at fault -- or even violating the Constitution -- with his invite to Netanyanhu.

After all, in 2007, then-Speaker of the House Nancy Pelosi went far beyond asking the leader of a friendly democracy to make a public speech to Congress. She went to Damascus to meet with Syrian dictator Bashar al-Assad, in a rebuke to President George W. Bush, who described the visit as "unhelpful."

Bush was right, but Pelosi's visit reflected the broader divide in U.S. policy: liberals have come to believe that the path to peace in the region -- and elsewhere -- is to engage with our declared enemies. Obama is merely continuing that approach.

Before he became secretary of state, John Kerry repeatedly visited Syria to woo Assad. When revolution came to Hosni Mubarak's Egypt, Obama was happier with the Muslim Brotherhood's regime than he was with the one that eventually overthrew it. And Obama's efforts to reach out to Iran began soon after he stepped into the Oval Office.

This doesn't amount to rejecting Israel's right to exist. But conservatives prefer to stand by our friends -- including Israel -- and that inclines liberals to believe that Israel is at fault: if what's needed is more outreach, those who oppose it are the problem. As liberal faith in engagement has grown over the decades, so has liberal resentment of both Israel and conservative support for it.

That's a sad delusion, because it leads liberals to minimize the evils of the regimes that they hope to befriend. Iran, after all, is the kind of place where the government thinks it's clever to respond to the Charlie Hebdo massacre by holding a Holocaust denial cartoon competition.

That's not clever. It's a sick, premeditated lie. And we shouldn't need a speech from the prime minister of Israel to remind us that regimes that lie about genocides won't hesitate to lie about their desire for an agreement with us, their support for terrorism -- or their nuclear programs.

 - Ted Bromund is a Senior Research Fellow at The Margaret Thatcher Center for Freedom.