President Donald Trump speaks as he signs the Waters of the United States (WOTUS) executive order, Tuesday, Feb. 28, 2017, in the Roosevelt Room in the White House in Washington, which directs the Environmental Protection Agency to withdraw the Waters of the United States (WOTUS) rule, which expands the number of waterways that are federally protected under the Clean Water Act. (AP Photo/Andrew Harnik)
President Donald Trump speaks as he signs the Waters of the United States (WOTUS) executive order, Tuesday, Feb. 28, 2017, in the Roosevelt Room in the White House in Washington, which directs the Environmental Protection Agency to withdraw the Waters of the United States (WOTUS) rule, which expands the number of waterways that are federally protected under the Clean Water Act. (AP Photo/Andrew Harnik) Credit: Andrew Harnik

WASHINGTON — Behind President Donald Trump’s efforts to step up deportations and block travel from seven mostly Muslim countries lies a goal that reaches far beyond any immediate terrorism threat: a desire to reshape American demographics for the long term and keep out people who Trump and aides believe will not assimilate.

In pursuit of that goal, Trump in his first weeks in office has launched the most dramatic effort in decades to reduce the country’s foreign-born population and set in motion what could become a generational shift in the ethnic makeup of the U.S.

Trump and top aides have become increasingly public about their underlying pursuit, pointing to Europe as an example of what they believe is a dangerous path Western nations have taken. Trump believes European governments have foolishly allowed Muslims with extreme views to settle in their countries, sowing seeds for unrest and recruitment by terrorist groups.

“Take a look at what’s happening in Sweden. Take a look at what’s happening in Germany. Take a look at what’s happened in France. Take a look at Nice and Paris,” Trump said Friday during a speech to the Conservative Political Action Conference, referring to riots last week in a predominantly Muslim neighborhood in Stockholm, as well as attacks in similar neighborhoods in Germany and France the last few years.

Critics of Trump’s travel ban, including several federal judges who have blocked it, have pointed to a lack of evidence that immigrants from those seven countries have engaged in terrorist acts in the U.S.

Two days after Trump imposed the ban, a senior administration official told reporters at the White House that the order was part of a larger strategy to develop an immigration system that selects immigrants they believe will make “positive contributions” to the country.

In their eyes, the U.S. has been spared mostly because its Muslim population remains much smaller than that of France, Germany or other European nations. Muslims make up about 7.5 percent of the French population, but only about 1 percent in the U.S., according to estimates by the Pew Research Center.

“Foreign terrorists will not be able to strike America if they cannot get into our country,” Trump said Friday.

But U.S. demographics have been changing rapidly — and undesirably in the eyes of top Trump aides, including his chief strategist, Stephen K. Bannon, and domestic policy adviser Stephen Miller. Inside the West Wing, the two men have pushed an ominous view of refugee and immigration flows, telling other policymakers that if large numbers of Muslims are allowed to enter the U.S., parts of American cities will begin to replicate marginalized immigrant neighborhoods in France, Germany and Belgium that have been home to plotters of terrorist attacks in recent years, according to a White House aide familiar with the discussions.

This alarms right-wing nationalists like Miller and Bannon, who see Trump’s administration as an opportunity to change those migration trends for decades to come. The two men see the country’s long-term security and wage growth entwined with reducing the number of foreign-born people allowed to visit, immigrate and work in the U.S. Nations, including the U.S., are undermined by too high a level of diversity, Bannon has argued.