In a report released Thursday, the Kaiser Family Foundation (KFF) found that President Donald Trump and congressional Republicans’ recent actions on healthcare legislation will likely cause double-digit insurance premium hikes for millions of Americans in 2018.

Amid repeated attempts by Republicans to destroy the Affordable Care Act (ACA) under the guise that it’s in a “death spiral,” and Trump’s troubling comments suggesting that his administration may try to sabotage the law that governs the U.S. national healthcare system, insurers are proposing to raise premiums for next year, scale back their offerings, or exit the exchange or individual market all together.   

“Since there has not been clarity on these issues, some insurers are already assuming that the Trump Administration or Congress may take an action that would destabilize the market,” KFF experts wrote last week.

“In many cases that means insurers are adding double-digit premium increases on top of what they otherwise would have requested,” Cynthia Cox, a co-author of the Kaiser report, told the Associated Press. “In many cases, what we are seeing is an additional increase due to the political uncertainty.”

And as AP noted, “That doesn’t sound like what Trump promised when he assumed the presidency.”

During the campaign and since his election, Trump repeatedly vowed to replace the current law with something “great” that would “take care of everybody.”

Although the ACA, also called Obamacare, applies to the whole U.S. healthcare system—including Medicaid, Medicare, employer-sponsored insurance, and coverage people buy on their own—Republicans’ actions are specifically affecting how insurers navigate exchange markets, or marketplaces, which first opened in 2014.

Thus, the premium hikes would have a targeted impact, as the AP reported on Thursday:

For the report released Thursday, KFF researchers examined preliminary premiums and insurer participation in D.C. and the major metropolitan areas of 20 states where filing details were publicly available for proposed costs of the second-lowest cost silver plan—which is “one of the most popular plan choices on the marketplace and is also the benchmark that is used to determine” financial assistance.