Forty-five percent of respondents said that they feel that the number of immigrants allowed to legally enter the country should be reduced; only 17 percent said they thought that number should increase. That’s in sharp contrast to opinions expressed six months ago in a February Pew Research Center poll, which found that nearly three-quarters of Americans would support a legal path to citizenship for undocumented immigrants.

That was before news broke in June that more than 50,000 unaccompanied children, mostly from El Salvador, Honduras, and Guatemala had been apprehended at the border since October. Since then, immigration has leaped to the forefront of the national dialogue in recent months.

Immigration could be a dominant issue in the upcoming midterm elections and could drive more Republican voters to the polls, Ipsos pollster Chris Jackson speculated in a Reuters interview. Immigration is already a contentious issue in Colorado, Arkansas, and Arizona. Even in New England, more than 2,000 miles from the border, Senate candidate Scott Brown has evoked immigration as a key issue. In May, Mr. Brown launched an offensive campaign ad criticizing incumbent Senator Jeanne Shaheen (D) of New Hampshire of “pro-amnesty policies.”