In one of his helicopter-tinged news conferences that are becoming a trademark of his administration, President Trump on Sunday was asked whether he had a message for Poland.

Trump was scheduled to attend a ceremony in Poland but sent Vice President Pence instead so Trump could monitor the situation with Hurricane Dorian.

“I just want to congratulate Poland. It’s a great country with great people,” Trump responded.

So what was he congratulating?

Unclear, but the ceremony he was supposed to attend commemorated the Nazi invasion of Poland 80 years ago.

This is what happened on Sept. 1, 1939: At dawn, the German Luftwaffe started bombing a Polish town called Wielun. By the time they were done, they had flattened nearly three-quarters of the city, including a hospital and a Gothic church. As many as 1,200 civilians were killed that day, according to the Polish government. There were no Polish troops stationed at Wielun, and destroying it served no strategic purpose — Nazi Germany attacked it simply to sow terror, according to the BBC.

In fact, Poland had mobilized late and was completely unprepared for the invasion, according to the U.S. Holocaust Memorial Museum. Poland had had a nonaggression agreement with Germany since 1934, but the Nazis invented a reason to violate it, staging a fake Polish attack on German radio.

A few hours after the attack began, Nazi leader Adolf Hitler went before the Reichstag and went on a tirade against Poland.

Two days later, France and England declared war on Germany, marking the start of World War II.

Over the following weeks, more than 2,000 German tanks and 1,000 German warplanes pulverized the western part of Poland. After the Germans surrounded Warsaw and bombed it, the city surrendered to the Nazis on Sept. 27, 1939.

Meanwhile the Soviet Union, which had secretly agreed not to defend Poland against the Nazis, invaded the eastern part of Poland, which fell on Oct. 6, 1939.

Over the next six years, Nazis killed at least 5 million Polish citizens, nearly 1 in every 5 citizens, according to estimates. More than half of them were Polish Jews.

The Nazis’ most notorious death camp, Auschwitz, where more than 1 million people were killed, is in southern Poland.

The Soviet Union liberated Poland in 1945, but it continued to struggle. A “compliant” government was promptly installed, according to the BBC, and Poland remained behind the Iron Curtain until 1989.

If “congratulations” for this from Trump seems out of place, then it may be just as well that Pence went in his place. As The Fix’s Aaron Blake wrote, Pence struck a solemn chord Sunday, saying, “It is difficult for any of us who are not Poles to fathom the horrors that began here 80 years ago, on this day.”

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