If there ever was a Trump crime worthy of impeachment, it was just committed in Syria.

In one feckless phone call, President Trump abandoned our loyal Kurdish allies, green-lit Turkish war crimes, spurred the revival of ISIS, helped the Kremlin and Iran, and sapped U.S. military morale. And then he went golfing.

Leading GOP senators are furious at Trump and urging severe sanctions against Turkey, with a bipartisan vote that will survive a Trump veto. Stung by criticism, an incoherent Trump now calls for weaker sanctions - for an invasion he endorsed. But sanctions will come too late to undo the damage. And they will be useless unless the GOP understands the real problem.

Trump’s phone call was not an unintentional error. It was vintage Trump. Left unchecked, he will cause more debacles.

In Syria (as with Ukraine), Trump is guilty of dereliction of duty. He has displayed gross unfitness for office. Let me count the ways.

1. Trump betrayed our most loyal Mideast Muslim ally.

The Syrian Kurds — a non-Arab ethnic group — were the key ground force that defeated ISIS. They lost 11,000 fighters. Without the Syrian Kurds, the United States would have had to send thousands of its own troops and take heavy losses, rather than 2,000 advisers and a loss of six troops.

Moreover, Trump’s dismissive claim that the Kurds were only fighting for “their land” is false. When I was in Rojava in 2016, Kurdish leaders were debating whether to sacrifice their young men and women to seize the ISIS capital, Raqqa, which is far from the Kurdish heartland; they made the decision to do so in order to cement their alliance with the United States.

» READ MORE: A Syrian Kurdish leader explains in 2018 why Trump withdrawal could bring disaster | Trudy Rubin

2. Trump’s withdrawal of 1,000 remaining U.S. troops from northern Syria won’t end “endless wars” — but will revive ISIS.

The president‘s decision was made so suddenly, and was so unplanned, that there was no time to secure prisons containing tens of thousands of ISIS fighters and their families. The Kurds had protected these prisons, but have withdrawn to fight back the Turks. Contrary to the president’s lies, only two high-value ISIS prisoners have been retrieved by the Americans.

The chaos of the Turkish invasion and the Kurdish withdrawal will give ISIS a new lease on life to reorganize as terrorists and threaten Israel, Arab allies, and the West.

3. Trump was easily rolled by Erdogan, a fellow autocrat who had Trump’s number.

An ignorant president swallowed the Turkish leader’s claim that he would take care of fighting “terrorists.” Had he taken the most minimal briefing, Trump would have known that Erdogan had pandered to ISIS, letting its fighters cross the Turkish border freely.

4. Trump gave the green light to war crimes.

Erdogan has sent jihadi militiamen into Syria who are eager to slaughter the more secular Syrian Kurds, especially their many female leaders. Political party head, Hevrin Khalaf, 37, was pulled from her car and shot dead on a highway. Erdogan’s expressed goal in Syria is to “ethnically cleanse” 500,000 Kurds out of Syria into Iraq and replace them with Syrian Arab refugees from inside Turkey, many of them hardcore Islamists. Everyone but Trump knew this — or he didn’t care.

» READ MORE: Turkey commits war crimes against Kurds with Trump's help | Trudy Rubin

5. Trump opened the door to the expansion of Russian and Iranian power in the region.

Desperate to survive, the Kurds have invited the Russian-backed Syrian government back into two cities that were about to fall to the Turks. Syrian leader Bashar al-Assad has been brutal to the Kurds in the past, but anything was preferable to Turkish slaughter. Perhaps Vladimir Putin will halt Erdogan’s invasion. Meantime, Iran will use the Kurdish disarray to expand its influence in northeastern Syria, to the detriment of Israel.

6. Trump dishonored our military.

Special forces operatives who considered Kurdish troops to be brothers are bitter at being forced to betray their comrades. Retired generals such as former Defense Secretary James Mattis and just-retired head of Central Command, Joseph Votel, have spoken out harshly against the withdrawal. They know Trump’s betrayal will make it much harder for U.S. forces to find local allies in the future.

7. Trump made America look weak and immoral to the world.

China, Iran, others have taken note. Instead of telling Erdogan “don’t you dare,” Trump retreated shamefully. Unlike Putin, who backs his allies, Trump casually discarded the Kurds..

8. Why did Trump do it?

Was it eagerness to keep his pledge to his base to end “endless wars” (and ignorance that he was starting new ones)? Was it visions of Trump towers in Istanbul and Moscow? What matters is that Trump sold out America, its values, its security, and its global standing — even as he consigned an ally to slaughter.

It couldn’t be clearer. Dereliction of duty. Unfitness for office. Full stop.