Politics isn't the only factor.

White House
Credit: Photo by Mark Wilson/Getty Images

International arrivals to the U.S. slumped by nearly 4 percent in the first six months of the year, according to the U.S. Department of Commerce National Travel and Tourism Office. The report tracks the arrivals of all non-residents, including business and pleasure travelers.

Arrivals from around the world dipped by 3.9 percent overall, with declines in visitors from every region except Canada, where there was an increase of about 5 percent.

The severity of the drop differed greatly region to region. Where European arrivals were down by only 2.6 percent, Mexican arrivals were down by nearly 10 percent, and arrivals from the Middle East dropped by nearly 30 percent.

Industry experts have long feared that some of President Donald Trump's divisive rhetoric would deter tourists from visiting the U.S., but many of those same experts have been slow to point the finger at the president, noting that sufficient data has not been collected to assert that the president caused the slump.

However, Trump's ban on visitors from certain Middle Eastern countries, several versions of which were put in place earlier this year, certainly appears to have limited visitors from the region, given the 30 percent drop.

“[Middle Eastern travel] was growing at a significant rate until January and then it just fell off a cliff,” said David Huether, senior vice president of research for U.S. Travel Association, a nonprofit representing the travel industry.

But Huether also pointed to the changing value of currencies as a potential culprit, noting that with a stronger dollar, some tourists might choose to go somewhere they can find a better exchange rate. The opposite is true for Canadians, whose currency has recently appreciated, potentially accounting for the increase in visitors from the Great White North.

The Associated Press suggested that recent mass shootings — in Texas, New York City, and Las Vegas — might have deterred visitors.

In response to the drop, Huether advocated for the U.S. to employ a more aggressive marketing strategy for personal and business travel, noting the importance of the nation's image abroad.

“The issue of perception is more important to international trade-related travel,” he said.