Supreme Court nominee Judge Brett Kavanaugh speaks in the East Room of the White House in Washington, July 9, 2018.

Brett Kavanaugh, whom President Donald Trump nominated Monday night to succeed on the Supreme Court, is widely viewed as a more conservative replacement for the retiring justice.

But legal experts say that while the judge has taken a more overtly pro-business stance than some of the other leading candidates on Trump's list, his rulings on such issues are unlikely to push the court much further to the right than with Kennedy on the bench.

Labor unions — including the AFL-CIO, the country's largest federation of unions — and workers' rights groups are still concerned, however.

"Judge Kavanaugh routinely rules against working families, regularly rejects the right of employees to receive employer-provided health care in the workplace, too often sides with employers in denying employees relief from discrimination in the workplace and promotes overturning well-established U.S. Supreme Court precedent," AFL-CIO President Richard Trumka said in a statement.

The labor organization sent CNBC a number of cases where it views Kavanaugh as having taken a stance against workers. In a 2015 case, for instance, Kavanaugh issued a ruling that favored the Venetian casino, which had requested that police issue criminal citations against union protesters whom the casino said were trespassing on private property.

A year earlier, Kavanaugh wrote the lone dissent in a case involving a SeaWorld trainer who had been killed by a killer whale during a performance.

That court had upheld a previous ruling that SeaWorld had violated workplace safety standards "exposing the trainers to recognized hazards when working in close contact with killer whales during performances." In an impassioned dissent, Kavanaugh said that lots of sports can be extremely dangerous and argued that the Labor Department had overextended its authority by attempting to regulate the whale show.

"When should we as a society paternalistically decide," Kavanaugh asked, "that the risk of significant physical injury is simply too great even for eager and willing participants? And most importantly for this case, who decides that the risk to participants is too high?"

Daniel Goldberg, legal director at the progressive advocacy group Alliance for Justice, was even more blunt than Trumka.

Goldberg said that while every name on Trump's list of 25 Supreme Court candidates poses a threat to Obama-era health-care laws and the abortion protections enshrined in the landmark 1973 Roe v. Wade ruling, Kavanaugh in particular represents a "who's who of protecting the wealthy and the powerful."

Goldberg's group points to Kavanaugh's rulings granting the Defense Department's authority to temporarily curtail some of its employees' collective bargaining rights, among other cases.

But Kavanaugh is not universally viewed as a reflexively anti-regulation judge. The Supreme Court tracker SCOTUSBlog counted a handful of cases where Kavanaugh wrote opinions upholding Environmental Protection Agency regulations and practices.

"Kavanaugh is clearly inclined to resist the expansion of administrative-agency authority, but he has tended to approach administrative law issues on a case-by-case basis," SCOTUSBlog wrote.

Eric Citron, a partner of the law firm Goldstein & Russell who clerked for Supreme Court Justices Elena Kagan and Sandra Day O'Connor, said that while Kavanaugh will likely be a conservative justice, "That does not distinguish him from Justice Kennedy, who was also a reliably conservative vote on most such issues."

Kavanaugh's opnions, Citron told CNBC, "show a strong bend away from claims by injured consumers, workers, unions, employees, and plaintiffs more generally," while noting that "Kavanaugh is a smart judge who tries to engage with the issues and keep an open mind, and for that should be appreciated as a nominee."

But, Citron said, "his natural inclination is friendly towards corporate defendants, and not their opponents in court."