With all the political orthodoxy that Donald J. Trump tore up in his convention speech on Thursday night, he set aside a core tenet of the American narrative on immigration: that the United States is a nation of nations, built on the sweat and initiative of people who came from other countries.

Using even darker language than he had on the campaign trail, Mr. Trump did not include even a boilerplate mention of positive contributions by immigrants. He described foreigners who came to the United States illegally and became killers of American citizens and drug dealers. More forcefully than he had before, Mr. Trump said he would also impose new restrictions on legal immigration to protect American workers from lower-paid competition in the labor market.

Under his presidency, the American dream would be primarily reserved for Americans.

“The American people will come first once again,” he said.