Gillespie did not comment on Trump's actions. Instead, he highlighted his own plans to reduce health-care costs in Virginia.
The Trump administration informed a federal court Friday that it would not make the "cost-sharing reduction payments," expected to total $7 billion, to insurers because the money was not formally appropriated by Congress. The move comes after congressional Republicans failed several times to pass legislation overhauling the Affordable Care Act.
Insurers depend on the cost-sharing payments authorized under the law to offset deductibles and other out-of-pocket costs for about 7 million people. Analysts expect companies to raise premiums or pull out of individual marketplaces as a result of Trump's action.
The precise impact on Virginia is unclear. In 2016, about 242,000 Virginians bought insurance plans that were subsidized through the federal program, according to the state attorney general's office.
Plans that will be sold in Virginia's ACA markets starting Nov. 1 already include a surcharge for the payments' suspension, which Trump had threatened for months.
The insurer Anthem in August cited uncertainty surrounding cost-sharing subsidies in its decision to pull out of Virginia's ACA marketplace, although it reversed course the next month. Anthem did not immediately respond Friday to a request for comment on its plans.
In a statement, Virginia Gov. Terry McAuliffe (D), who cannot seek consecutive terms under the state constitution, said Trump's actions risk "a full blown public health crisis across our country."
While Virginia had already planned for the subsidy cuts for 2018, McAuliffe's spokesman said insurers in future years could raise prices further or pull out entirely.
"Because of the way the Trump administration has handled this whole thing, there were already significant rate increases, these companies baking in and preparing for the worst," Brian Coy said. "They are going to set rates again, and we have every expectation that rates will go up again."
Northam, a pediatric neurologist and McAuliffe's lieutenant governor, has sought to channel voter anxiety about the federal health-care debate.
"For too long, Republican leaders have allowed President Trump to play politics with people's lives," Northam said in his statement. ". . . It is time for leaders on both sides of the aisle to put a stop to the uncertainty and work on stabilizing and building on the Affordable Care Act's progress."
Gillespie, a longtime GOP operative and the party's 2014 U.S. Senate nominee, declined to weigh in on Trump's move to end the payments when asked Friday on WAMU's "Kojo Nnamdi Show" and later through a spokesman. He said Virginia should increase competition in the insurance market by forming a regional compact allowing plans to be sold across state lines. His spokesman, David Abrams, said that Virginia "can't rely on Washington, D.C., to solve our problems."
Attorney General Mark Herring, a Democrat running for reelection, said Friday that Virginia will join several other jurisdictions, including Maryland, California and the District of Columbia, that are suing the Trump administration over the end of the subsidies.
Virginians will go to the polls Nov. 7.