Shortly after he took office on Monday, California's Democratic Gov. Gavin Newsom unearthed an unprecedented new health care agenda for his state, aimed at offering dramatically more benefits to illegal immigrants and protecting the embattled Affordable Care Act, which a federal judge recently struck down as unconstitutional.

The sweeping proposal appeared destined to push California -- already one of the nation's most liberal states -- even further to the left, as progressive Democrats there won a veto-proof supermajority in the state legislature in November and control all statewide offices.

"People's lives, freedom, security, the water we drink, the air we breathe — they all hang in the balance," Newsom, 51, told supporters Monday in a tent outside the state Capitol building, as he discussed his plans to address issues from homelessness to criminal justice and the environment. "The country is watching us, the world is watching us. The future depends on us, and we will seize this moment."

Newsom unveiled his new health-care plan hours after a protester interrupted his swearing-in ceremony to protest the murder of police Cpl. Ronil Singh shortly after Christmas Day. The suspect in Singh's killing is an illegal immigrant with several prior arrests, and Republicans have charged that so-called "sanctuary state" policies, like the ones Newsom has championed, contributed to the murder by prohibiting state police from cooperating with federal immigration officials.

As one of his first orders of business, Newsom -- who also on Monday requested that the Trump administration cooperate in the state's efforts to convert to a single-payer system, even as he bashed the White House as corrupt and immoral -- declared his intent to reinstate the ObamaCare individual mandate at the state level.

ANALYSIS: AS CALIFORNIA'S PROGRESSIVE POLICIES GET CRAZIER, WHAT'S THE SILVER LINING FOR THE GOP?

The mandate forces individuals to purchase health care coverage or pay a fee that the Supreme Court described in 2012 as a "tax," rather than a "penalty" that would have run afoul of Congress' authority under the Commerce Clause of the Constitution. Last month, though, a federal judge in Texas ruled the individual mandate no longer was a constitutional exercise of Congress' taxing power because Republicans had passed legislation eliminating the tax entirely -- a move, the judge said, that rendered the entire health-care law unworkable.

As that ruling works its way to what analysts say will be an inevitable Supreme Court showdown, Newsom said he would reimpose it in order to subsidize state health care.

Medi-Cal, the state's health insurance program, now will let illegal immigrants remain on the rolls until they are 26, according to Newsom's new agenda. The previous age cutoff was 19, as The Sacramento Bee reported.

Additionally, Newsom announced he would sign an executive order dramatically expanding the state's Department of Health Care Services authority to negotiate drug prices, in the hopes of lowering prescription drug costs.

In his inaugural remarks, Newsom hinted that he intended to abandon the relative fiscal restraint that marked the most recent tenure of his predecessor, Jerry Brown, from 2011 to 2019. Brown sometimes rebuked progressive efforts to spend big on various social programs.

"For eight years, California has built a foundation of rock," Newsom said. "Our job now is not to rest on that foundation. It is to build our house upon it."

Newsom added that California will not have "one house for the rich and one for the poor, or one for the native-born and one for the rest."

"The country is watching us, the world is watching us." — California Democratic Gov. Gavin Newsom

In a statement, the California Immigrant Policy Center backed Newsom's agenda.

“Making sure healthcare is affordable and accessible for every Californian, including undocumented community members whom the federal government has unjustly shut out of care, is essential to reaching that vision for our future,” the organization said. “Today’s announcement is an historic step on the road toward health justice for all.”

CLICK HERE TO GET THE FOX NEWS APP

The Sacramento Bee reported on several of Newsom's recent hires, which seemingly signaled he's serious about his push to bring universal health care to California. Chief of Staff Ann O’Leary worked in former President Bill Clinton's administration on the Children’s Health Insurance Program (CHIP), which offers affordable health care to children in families who exceed the financial threshold to qualify for Medicaid, but who are too poor to buy private insurance.

And, Cabinet Secretary Ana Matosantos, who worked in the administrations of Brown and former GOP Gov. Arnold Schwarzenegger, has worked extensively to implement ObamaCare in California and also worked with the legislature to expand health-care coverage for low-income Californians.

Fox News' Andrew O'Reilly and Corbett Riner contributed to this report.