Californians will still have access to a broad range of health insurance plans, coverage guarantees and income-determined subsidies when the state’s health insurance exchange, Covered California, opens enrollment today for 2019.

That’s good news, but state residents should remain wary of ongoing federal attempts to destabilize the current health care system, several health care advocacy groups warned last week in advance of the mid-term elections. If successful, these efforts could upend California’s progress toward decreasing the state’s uninsured rate, and leave millions of people vulnerable to inferior health insurance coverage or having no coverage at all, they said.

“These past few years, Californians and people across the country have experienced really serious federal threats that would jeopardize their ability to keep their coverage that they have now,” said Claire McAndrew, director of campaigns and partnerships with the national health advocacy group FamiliesUSA. “Our current Congress came within just a few votes of repealing the Affordable Care Act, and there are many people seeking election for the next congress who have promised to try to repeal the health care law yet again if they are sent to Washington.”

According to Covered California, residents seeking health coverage are already experiencing negative impacts following the repeal of the “individual mandate” in the Republican-led tax reform passed in 2017. That mandate, part of the Obama-era Affordable Care Act, required individuals who didn’t purchase health insurance to pay a fine. Republicans argued the mandate unfairly forced people to buy insurance they didn’t want. But the repeal is expected to result in more people dropping out of the insurance pool, pushing premiums up for everyone else. Carriers added an average of 3.5 percent to their rates for next year as a result of this change, Covered California has said.

Meanwhile, other attempts to undermine current health care provisions loom on the horizon. California’s Attorney General Xavier Becerra is leading the fight against a lawsuit filed by Texas and 19 other Republican states that seeks to overturn the Affordable Care Act. Republican lawmakers have floated proposals to cap funding for Medicaid, the government health care plan for low-income people, known as Medi-Cal in California. And the Trump administration has proposed denying green cards to legal immigrants who access public benefits such as Medi-Cal and food stamps.

California has proactively tried to shield itself from some federal actions. For example, Gov. Brown recently signed a law that bans the sale of cheap, short-term insurance plans in the state. Nationally, the Trump administration has moved to allow these plans, touting them as a cheaper alternative to Obamacare. However, the plans don’t have to meet the same standards as ACA plans, and can deny coverage to people with pre-existing conditions, as well as exclude services such as maternity, pediatric and mental health care. Denying coverage to people with pre-existing conditions would affect more than 16 million people in the state, according to FamiliesUSA.

However, the state does not have the power to fully protect itself from federal actions, particularly since it relies on billions of dollars in health care funding from the federal government, advocates said. They urged Californians to consider this as they cast ballots for state and congressional representatives in November.

“California is not an island, we are very much dependent on what’s going on at the federal level,” said Anthony Wright, executive director of the statewide health advocacy group Health Access California. “We urge Californians to sign up for coverage, but then continue to fight like hell to keep the benefits.”