The nonpartisan, nonprofit organization looks at 12 economic, social, and political indicators each year to create the Fragile States Index, giving nations a rating from “sustainable” to “alert” based on their risk of instability.

Mexico and Ethiopia saw the greatest decline, according to the index. Turkey, Brazil, South Africa, and the Gambia also trended downward.

Political division in the U.S. and the United Kingdom contributed to a decline for both countries, according to J.J. Messner, executive director of the Fund for Peace.

For the U.S., economic strength kept the nation from falling farther in the rankings.

“On indicators like economics the United States is doing pretty well,” said Messner, “but there is this core group of indicators—security, factionalized elites, and group grievance—where the United States is doing quite poorly.”

Factors in the U.S. such as police violence and the public unrest it caused, gridlock among national leaders and deep political division led to significant deterioration of these three indicators out of 12 used to score each nation.

Security looks at the relationship between security forces and citizens of each nation, while the factionalized elites indicator considers representative leadership and the divisions among those in power.

The group grievance indicator, which Messner describes broadly as schisms in society, was particularly surprising in the last year. This measure can encompass issues ranging in inequality along ethnic and religious lines, hate speech and divisive rhetoric, and violence and hate crimes.

After the Brexit vote in 2016, researchers at the fund examined the group grievance score for both the U.K. and the U.S. over the last five years and found that the countries tied for the seventh most worsened position in that time period.

“For a developed country to have worsened that much on any indicator without some sort of natural disaster or something like that was quite remarkable,” Messner said.

And it’s getting worse. By the same measure for 2017, the U.S. ranks the fourth in the world.

While these indicators are all measured individually, they are very interconnected.

“When the economy takes a downturn, as it inevitably will, then I think that will just serve to exacerbate existing problems that are already starting to boil up,” Messner said of the poor U.S. performance on social and political indicators.

The full 2017 index isn’t entirely bad news. Cuba was the most improved country over the past 10 years, and Colombia achieved peace after a half-century of conflict.

Still, rising nationalism in the U.S. and elsewhere has many citizens and leaders debating foreign policy commitments, and Messner stressed the importance of stability abroad for security at home.

“State fragility on the other side of the world has a direct effect on Americans domestically,” he said. “America not only has to recognize that there are these effects, but also understand that America can play an incredibly pivotal role in mitigating.”