Turkish President Recep Tayyip Erdogan has done it again.

In his usual intemperate style, he’s accused two friendly countries, the Federal Republic of Germany and Holland, of behaving like Nazi Germany. The comparison is absurd, but lest we forget, Erdogan has also levelled this odious accusation against Israel, not once but twice.

Clearly, he’s a loose cannon.

Erdogan’s fired his latest rhetorical blast several days ago, claiming the German government had used “Nazi practices” to prevent him or his surrogates from delivering speeches in Germany in connection with a referendum scheduled to be held in Turkey on April 16.

Erdogan declared a state of emergency in Turkey after last summer’s failed coup d’état, and now seeks to expand his already considerable powers by means of a new constitution. If he can win the support of most of the 1.5 million Turks in Germany eligible to vote in the upcoming referendum, he may be able to move closer to achieving this objective.

German Chancellor Angela Merkel expressed concerns about Turkey’s arrest of thousands of political opponents and its crackdown on civil liberties since the botched coup. Nonetheless, she let it be known that Turkish leaders could campaign in Germany if they notified the authorities in advance and respected German laws. German muncipalities, however, banned such appearances, prompting Erdogan to blurt out, “I thought Nazism had ended in Germany. Turns out it’s still going on, plain and visible.”

Understandably enough, Erdogan’s outrageous comments upset Merkel. Speaking to the German parliament on March 9, she correctly described his remarks as “sad and incredibly misplaced,” suggesting his comparison had trivialized the suffering of Nazi victims.

Having insulted Germany, Erdogan went ballistic today after the Dutch government refused to let the Turkish foreign minister’s plane to land so he could address a rally in the port of Rotterdam. “They are the vestiges of the Nazis, they are fascists, ” he charged.

Understandably, Dutch Prime Minister Mark Rutte was not amused. “It’s a crazy remark, of course,” he said.

Rutte was right to upbraid Erdogan, whose explosive temper has affected Israel.

In 2010, after Israeli commandos boarded the Mavi Marmara, a Turkish ship trying to break Israel’s naval siege of the Hamas-controlled Gaza Strip, Erdogan lashed out at Israel, accusing it of “keeping Hitler’s spirit alive.”

Erdogan’s emotionally-charged language was totally inappropriate, but during Israel’s 2014 war with Hamas in Gaza, he went off on a linguistic tear yet again, wildly claiming its “barbarism” surpassed that of Nazi Germany.

Given his abysmal track record, no one should be surprised by Erdogan’s latest verbal outbursts, aimed at Germany and Holland, where about 400,000 ethnic Turks live. Erdogan is a thin-skinned politician who cannot tolerate legitimate criticism. Worse still, his grasp of history is extremely shaky.

He should think carefully before he opens his big mouth again, but that may be asking too much of Erdogan, a self-possessed, arrogant politician who shoots from the hip.

While Erdogan’s heated rhetoric is highly objectionable, his authoritarian methods are even more repelling.  Norbert Lammert, the president of Germany’s parliament, has warned that Erdogan’s victory in the forthcoming referendum could push Turkey in the wrong direction. It could well transform Turkey — the only Muslim state in NATO — into an “increasingly autocratic state” at odds with “European values and standards.”

This a development that hardly bodes well for Turkish aspirations of European Union membership. In principle, Turkey should be admitted into the EU. But if Erdogan succeeds in turning Turkey into a full-fledged authoritarian state, Europe would be well within its rights to ostracize Turkey and wait for a more reasonable Turkish leadership to emerge in Ankara.