Nearly three-in-five American voters say barriers, fences, and walls at the United States-Mexico border are effective in stopping illegal immigration, a new poll finds.

The latest Harvard/Harris Poll reveals sweeping agreement among the American electorate when it comes to the use of border walls at the U.S.-Mexico border to stop illegal immigration. About 57 percent of voters said a border wall at the southern border is either very or somewhat effective in stopping illegal immigration.

Likewise, a border wall to stop illegal immigration is popular with most swing voters. About 55 percent of Independents said they believed a wall was very or somewhat effective in stopping illegal immigration to the U.S.

Even across racial lines, Americans are more likely than not to say a border wall works.

The majority of white Americans, Hispanics, and black Americans agree that a border wall is effective at the southern border. About six-in-ten white Americans, along with 51 percent of black Americans and 51 percent of Hispanic Americans, said the wall works in terms of stopping illegal immigration.

Republicans, conservatives, Trump supporters, and rural voters are all the most likely out of any group to support the border wall’s effectiveness. Roughly 74 percent of GOP voters, 78 percent of conservatives, 79 percent of Trump supporters, and 66 percent of rural voters said the border wall is very or somewhat effective.

While the border wall has long been supported by the majority of Americans, there has been little progress thus far at constructing a new wall at the southern border. Only about 40 miles of replacement fencing have been built, although about 124 miles of new wall and replacement fencing has been approved by Congress. This month, about 14 miles of new wall is expected to be constructed in southern California. This will serve as the first new barrier built under Trump.

This year, researchers project that up to 500,000 illegal aliens will successfully cross the U.S.-Mexico border and make it into the country, undetected by Border Patrol, unless drastic advances are taken in border wall construction and closing legal loopholes at the border. Similarly, the country is on track for more than 600,000 border apprehensions in 2019, a level of illegal immigration that has not been seen since former President George W. Bush.

John Binder is a reporter for Breitbart News. Follow him on Twitter at @JxhnBinder.