Corporate interests haven’t had it so good at the Supreme Court in a long time.

Under Chief Justice John Roberts Jr. the court has given big business a leg up on workers, unions, consumers and the environment — and will do so even more aggressively if the Senate confirms Brett Kavanaugh, President Trump’s choice to replace Justice Anthony Kennedy.

Corporations won the power to spend unlimited amounts of money on political campaigns in the 2010 Citizens United decision. The owners of businesses have earned the right to cite their personal religious beliefs to deprive workers of reproductive health care. At the same time, the justices have made it harder for employees and customers to sue big businesses by allowing corporations to require mandatory arbitration clauses in contracts people are forced to sign if they want jobs or want to buy goods and services. The court has also made it easier for polluters to get away with poisoning the air and water.

In many of these decisions the five conservative justices have shown no restraint in rejecting judicial precedent and in substituting their own judgment for that of lawmakers. Just last month, in a blow to public-sector unions with contracts covering nearly seven million workers, their 5-to-4 ruling dismissed a unanimous 40-year-old decision that state governments and unions had long relied on. In the recent case, Janus v. American Federation of State, County and Municipal Employees, the court held that government workers covered by union contracts do not have to pay fees for collective bargaining expenses if they are not members. The ruling does not directly involve businesses. But it will hurt all workers because benefits won by unions often establish benchmarks that help improve wages and working conditions even at companies without unions.

Under the Roberts court, between 2005 and 2015, when businesses were either plaintiffs or respondents but not both, businesses prevailed 61 percent of the time, according to a study by Lee Epstein, William Landes and Richard Posner published last year. That compares with a rate of 44 percent when Chief Justice William Rehnquist led the court from 1986 to 2004, and 43 percent when Warren Burger was chief justice from 1969 to 1986.

Analysts have also looked at how rulings compare with positions advocated by the U.S. Chamber of Commerce. That organization has been an aggressive champion for the legal interests of big business since at least 1971, when Lewis Powell, later a justice on the Supreme Court, wrote an influential memorandum calling on the group’s leaders to see the court as a “a vast area of opportunity for the Chamber, if it is willing to undertake the role of spokesman for American business and if, in turn, business is willing to provide the funds.”

Mr. Powell was prescient. The Roberts court has sided with the chamber 70 percent of the time from 2006 through the term that concluded a few weeks ago, according to the Constitutional Accountability Center. By comparison, the Rehnquist court ruled in favor of the chamber’s position 56 percent of the time between 1994 and 2005 and the Burger court ruled for it 43 percent of the time between 1981 and 1986, years during which there were no changes in the court’s membership.

Neither the Rehnquist nor the Burger courts could be considered liberal, but the justices that served on them were more likely to have heterodoxpolitical views, regardless of whether they were appointed by Republican or Democratic presidents. Over the years, conservative groups like the Federalist Society and the Heritage Foundation have worked to make sure that Republican presidents appoint judges and justices who are reliably pro-corporate. Partly as a result, the Roberts court has been much more adamant in opposing regulation and much more expansive in establishing corporate rights. Chief Justice Roberts and Justice Samuel Alito Jr., both appointed by President George W. Bush, are the most pro-corporate justices since 1946, according to the Epstein, Landes and Posner research.

Judge Kavanaugh, who serves on the United States Court of Appeals for the District of Columbia Circuit, fits neatly into the Roberts-Alito worldview.

In 2012, Judge Kavanaugh wrote an appeals court opinion striking down an Environmental Protection Agency rule that required upwind states to reduce power plant emissions that cause smog and soot pollution in downwind states, a decision that was later struck down by a 6-to-2 majority of the Supreme Court. And in 2016, he wrote an opinion that said the leadership structure of the Consumer Financial Protection Bureau was unconstitutional because Congress decided that the president could only fire its director for cause. The full appeals court reversed that portion of his decision in January.

In a dissent last year from a decision involving net neutrality rules put in place by the Federal Communications Commission, Judge Kavanaugh wrote that the F.C.C. did not have the authority to issue the rules — despite a Supreme Court ruling saying it did. He wrote that by prohibiting broadband companies from interfering with information that customers tried to get over the internet, the rules violated the companies’ First Amendment rights. As the majority noted, his interpretation would allow a broadband company to hold itself out as a neutral provider of access to all websites, then block or impede access to competing services.

Judge Kavanaugh dissented again when the appeals court upheld a Department of Labor decision that found SeaWorld had violated workplace safety laws by not adequately protecting a trainer who was killed by the orca Tilikum, made famous by the movie “Blackfish.” The judge argued that the department overstepped its authority by regulating sports and entertainment — something he argued it had not done before. In fact, the government has previously regulated safety in the entertainment industry and other workplaces where workers were killed by dangerous animals.

The court’s pro-corporate decisions are widening the chasm in power and wealth between the country’s elite and everybody else. And the Roberts court is also increasingly preventing lawmakers, regulators and the public from doing anything about that growing problem.