Judge Reed O'Connor's ruling declaring the entire Affordable Care Act, or Obamacare, unconstitutional took many experts by surprise.

Many health-policy experts questioned O'Connor's legal judgement and pointed to his long history of favoring conservative positions and attacking the ACA.

The experts also agreed that the ruling would likely be overturned.

The shock decision by Judge Reed O'Connor on Friday that ruled the Affordable Care Act (ACA), or Obamacare, is unconstitutional was made with a partisan tinge and likely will not stand, experts said.

Health-policy experts from across the political spectrum rejected O'Connor's reasoning for the decision and expected it would be overruled on appeal.

O'Connor's decision determined that when Congress reduced the ACA's individual mandate — or penalty for not having health insurance — to $0, the rest of the law became effectively unconstitutional. This is a broad view of Congress' intent, legal scholars said.

"Congress amended one provision of a 2,000 page law and did not touch the rest of the law so it is implausible to believe that Congress intended the rest of the law not to exist," Abbe Gluck, a health-law expert at Yale Law School, said following the ruling.

Under O'Connor's decision, the entirety of the ACA would be thrown out, including popular provisions like preexisting-condition protections. Given that such changes could throw the healthcare system into chaos and leave as many as 20 million people without insurance, the ruling has caused an uproar among both politicians and healthcare advocates.

In a Washington Post op-ed, Nicholas Bagley, a law professor with a focus on health policy at the University of Michigan, failed to make sense of O'Connor's legal case. He determined that the "logic of the ruling is as difficult to follow as it is to defend."

"This case is different; it's an exercise of raw judicial activism," Bagley said. "Don't for a moment mistake it for the rule of law."

O'Connor has been labeled a favorite judge of conservative lawyers and has ruled against Obamacare on numerous occasions.

And even many Obamacare critics have spoken out against the ruling. Conservative lawyers that previously criticized the law took issue with the breadth of the ruling. Philip Klein, the executive editor of the conservative-leaning Washington Examiner and author of a book on "overcoming" Obamacare, called it an "assault on the rule of law."

"If Congress repealed all of Obamacare tomorrow, I'd throw a party. Despite my policy preferences, I'd say the latest decision from U.S. District Court Judge Reed O'Connor of Texas declaring Obamacare unconstitutional is an assault on the rule of law," he wrote in an op-ed Monday.

While most experts agree that O'Connor overstepped, the prevailing sense is that nothing will change for the time being.

The judge issued what is known as a declaratory judgment — which, unlike an injunction, allows the law to continue unabated until the case is taken up by another court. Democratic states have pledged to appeal the ruling, so O'Connor's decision will likely not be the last word. Meanwhile, people who get access to healthcare through Obamacare's marketplaces or Medicaid expansion will continue to have coverage.

Looking to the future, many health policy experts also believed a higher court — whether it's an appellate court or Supreme Court — will eventually reject O'Connor's huge scope.

"This is insanity in print, and it will not stand up on appeal," Bagley tweeted on Friday.