Every year around July Fourth I think of my immigrant grandparents who made their way as teenagers by foot and cart from rural Russia to Hamburg, Germany, and then traveled in the bowels of a steamship to Ellis Island in 1905.

If not for them, I wouldn’t be celebrating the birth of our country. Nor would I be as aware of the rich legacy that immigrants have brought to this nation. Moreover, had America not received them, my grandparents would almost certainly have died in 1941, when Nazis overran their hometown, marched its 3,100 Jews into a forest, and shot them.

So I take the current corrosive debate over the value of immigration very personally. Which is why I chose to visit the U.S. Holocaust Memorial Museum’s fascinating new exhibition on Americans and the Holocaust last week, with its gripping examination of an era when immigrants were made unwelcome.

The exhibit is solely focused on the pre-World War II years of the late 1930s and early 1940s (complete with newsreels and cinema clips of WWII movies). But there are eerie resonances with now.

“What we see in the exhibit are some enduring questions about how Americans debate their responsibilities in the world,” says Daniel Greene, the exhibit’s curator and a specialist in U.S. immigration history. “In this case, when Germany falls apart, whether to aid refugees or people targeted for murder. These questions don’t go away.”

On Nov. 9 and 10, 1938, during the so-called Kristallnacht pogrom, thousands of Jewish businesses, cemeteries, and synagogues were attacked, while Jews were beaten and robbed. Soon after, 30,000 Jewish males were sent to early concentration camps. By then, around 309,000 German Jews were frantically seeking U.S. visas, but the annual U.S. quota for German refugees was only 27,000.

German Jewish parents were so desperate to save their children that they were willing to send them to America alone. In 1939, a bipartisan team of Sen. Robert Wagner, D-N.Y., and Rep. Edith Nourse Rogers, R.-Mass., proposed a bill to provide visas for 20,000 German Jewish children above existing quotas. The bill never came to the House floor, due to ardent opposition from white Southern Democrats. First lady Eleanor Roosevelt urged her husband to support the bill, but he demurred.

Many, if not most, of the children who could have been saved probably perished.

The exhibit profiles courageous Americans who conducted their own rescue missions, including Eleanor and Gilbert Kraus, a Philadelphia Jewish couple who extricated 50 Jewish children from Nazi-occupied Vienna (and found State Department officials willing to grant them U.S. visas).

But on the whole, the State Department stubbornly resisted letting Jewish emigres in, refusing even to fill the existing annual legal quota, let alone increase it. And the public backed it: In 1938, two weeks after Kristallnacht, a poll showed that 98 percent of Americans disapproved of the Nazis, but 72 percent disapproved of letting in more Jews.

So why, in a country that had considered itself a land of immigrants, was there such a resistance to saving victims of the Nazis?

Anti-Semitism played a major role, but so did fear of economic competition (in the decade of the Great Depression), along with isolationism, xenophobia, and racism.

You can watch newsreel footage of the infamous Rev. Charles E. Coughlin, a highly popular white Catholic nationalist; he preached over radio and to mass rallies that “we need to restore America to the Americans. in the name of Christianity.”

Then there was the aviation hero Charles Lindbergh, whose isolationist America First movement demanded that America stay out of World War II, and who damned the Jews for “wanting us to go to war.” In this atmosphere, outright white supremacist groups such as the Silver Legion of America flourished.

Comparisons between then and now are clearly inexact, but, to me, the most ugly is our government’s attitude towards war refugees from Syria. Regime and Russian war crimes have killed hundreds of thousands of civilians, whose death by barrel bombs and poison gas can be seen on YouTube. Yet the United States admitted only 3,000 Syrian refugees in 2017 and 11 so far this year.

The most shameful comparison is with the Trump administration’s treatment of refugee children, separating them from parents fleeing lethal violence in Central America and seeking asylum in the U.S.

But the most fascinating comparison has to do with the issue of legal immigration, which the Trump administration is openly trying to cut by half. Unlike the 1930s, American public support for legal immigration is rising. A June poll by the Pew Research Center found that 38 percent said legal immigration should be kept at its present level, while 32 percent want it to increase and only 24 percent say it should be decreased.

In other words, despite the endless xenophobic and America First rhetoric from President Donald Trump, most Americans still appreciate the contributions that immigrants make to this country.

Trudy Rubin is a columnist and editorial-board member for the Philadelphia Inquirer.