MIAMI, FLORIDA - JANUARY 28: A pedestrian walks past the Leading Insurance Agency, which offers plans under the Affordable Care Act (also known as Obamacare) on January 28, 2021 in Miami, Florida. President Joe Biden signed an executive order to reopen the Affordable Care Act's federal insurance marketplaces from February 15 to May 15. (Photo by Joe Raedle/Getty Images)
CNN  — 

A record number of people signing up for Obamacare policies. Nine more states expanding Medicaid coverage to more than 2 million adults. Much higher favorability ratings among the public. Another victory for the landmark health reform law in the nation’s highest court.

These are among the main reasons why it would be even tougher than it was in 2017 for Republicans to try to dismantle the Affordable Care Act, even if they secure control of the White House and Congress next year.

The 13-year-old law is even more embedded in the nation’s health care system than it was when former President Donald Trump took office, vowing to kill Obamacare. But he and the Republican lawmakers who controlled Congress ultimately failed to repeal and replace the Affordable Care Act after months of unsuccessful attempts to come up with an alternative.

Obamacare’s future is once again in the spotlight after Trump, who is running for the 2024 GOP presidential nomination, unexpectedly posted on his Truth Social site last month that Republicans should “never give up” trying to terminate the law and that he would replace it with “MUCH BETTER HEALTHCARE.”

Florida Gov. Ron DeSantis, who is also vying for the Republican nomination, followed suit, saying that he would “replace and supersede” the Affordable Care Act with “a better plan” since “Obamacare has not worked.” The law took plenty of heat during Wednesday’s fourth GOP presidential debate.

But most of the nation, particularly Republican voters and many GOP lawmakers, have moved on from trying to repeal and replace the law.

And while Obamacare had a rocky start, with enrollment coming lower than expected in the federal and state exchanges, insurers dropping out of the marketplaces and many Republican-led states refusing to expand Medicaid, it has since stabilized.

More than 40 million Americans now have health care coverage thanks to the Affordable Care Act, up from just under 27 million in 2017, according to the Department of Health and Human Services. Obamacare’s popularity increased after congressional Democrats enhanced the federal premium subsidies in 2021.

Many more people benefit from the law’s provisions that protect people with preexisting conditions from being turned away or charged higher premiums by insurers, allow children to remain on their parents’ plans until age 26 and provide an array of preventive services at no cost.

“We’re as close as we’ve been to meeting the aspirational goals of 2010 for the ACA,” said Rodney Whitlock, vice president at McDermott+Consulting and a former health policy adviser on the Senate Finance Committee under Republican Sen. Chuck Grassley of Iowa. “It was still in its infancy in 2017. Now it has matured enough that it is stable and functioning.”

Here is why the Affordable Care Act would be more difficult to dismantle now.

Record interest in Obamacare coverage: More people are insured through the Affordable Care Act exchanges than ever before. Some 15.7 million people were enrolled in Obamacare plans in February, up 13% from a year earlier, according to the Centers for Medicare and Medicaid Services, which oversees the exchanges. Plus, 1.5 million more people enrolled between March and September, compared with the same period in 2022.

Americans are continuing to flock to the exchanges for 2024 coverage too. Nearly 7.3 million people have selected plans in the first five weeks of this year’s open enrollment period, which began November 1. That’s an increase of nearly 34% from roughly the same period a year earlier.

Spurring much of this interest are the hefty federal premium subsides that are available through 2025. President Joe Biden and congressional Democrats beefed up the assistance as part of the 2021 American Rescue Plan Act and renewed the enhancement as part of last year’s Inflation Reduction Act. The expanded subsidies enable 4 out of 5 people to find a plan for less than $10 a month. Some 91% of enrollees were receiving subsidies as of February.

In 2017, only 10.3 million people were enrolled in Affordable Care Act plans.

Also, those signing up for coverage now have far more choice of insurers and policies than they did in 2017. Some 210 health insurance issuers are participating on the federal exchange, healthcare.gov, in 2024. The average enrollee has just under seven issuers to pick from.

But there were only 167 issuers participating in 2017, and the average consumer had only three to choose from. Several large insurers, including Aetna, Humana and UnitedHealthcare, had announced they were scaling back participation in 2016.

More states implement Medicaid expansion: There are now 40 states that have adopted the Obamacare provision expanding Medicaid coverage to more low-income adults. That’s nine more than in 2017.

In most of the states, voters forced resistant Republican-led legislatures to broaden Medicaid by approving ballot initiatives. Maine began the trend in 2017, though it wasn’t implemented until a Democratic governor took office in 2019. Idaho, Nebraska, Utah, Missouri and Oklahoma followed, with South Dakota becoming the latest to adopt Medicaid expansion at the ballot box in 2022.

Virginia expanded Medicaid in 2018, while North Carolina did so on December 1. In each of these two states, Democratic and Republican officials worked together to adopt the provision after years of resistance by the GOP.

Nationwide, nearly 18.8 million newly eligible Americans were enrolled in Medicaid as of September 2022, according to the Department of Health and Human Services. In 2017, that figure was 12.2 million.

Higher favorability ratings: Nearly 60% of adults have a favorable view of the Affordable Care Act, close to the highest share since the law was passed in 2010, according to the KFF Health Tracking Poll.

That’s quite a difference from December 2016, when only 43% had a favorable opinion of Obamacare.

Another change: The law’s future is more important to Democratic voters than Republican ones, according to a different KFF poll. Overall, 49% of voters said the issue is “very important,” but breaking it down by party, 70% of Democratic voters felt that way, while only 32% of Republican voters did. Obamacare had been a key health care issue for GOP voters in the past.

Supreme Court leaves law intact: After Congress failed to repeal Obamacare, a coalition of GOP-led states and the Trump administration tried to take it down through the US court system.

The states argued the act’s individual mandate was rendered unconstitutional when Congress in 2017 reduced the penalty for not having coverage to $0. They also contended that because the mandate was intertwined with a multitude of other provisions, the entire law should fall.

But the Supreme Court dismissed the lawsuit in 2021, saying the challengers did not have the legal right to bring the case.

The case marked the third time the law survived a significant challenge in the Supreme Court.