President Trump Supreme Court nominee Brett Kavanaugh in 2012 sided with the future U.S. president's casino in a case over unionization, Bloomberg reported.

Kavanaugh threw his weight behind Trump Entertainment Resorts' successful attempt to end a unionization effort at one of its casinos six years ago.

He voted with two other Republican-nominated judges on the D.C.-based federal appeals court to set aside an order by the National Labor Relations Board (NLRB) that would have required the Trump Plaza Hotel and Casino in New Jersey to bargain with the United Auto Workers.

Labor advocates point to this ruling as evidence that Kavanaugh's appointment could lead to the targeting of laws to protect workers and specifically target the dwindling number of unions in the U.S.

"Kavanaugh, along with Thomas, Alito, Gorsuch - and Roberts along for the ride - will comprise the most radical, anti-labor-law Supreme Court in my lifetime," University of Wyoming law professor Michael Duff, a former attorney for the NLRB, told Bloomberg.

The Atlantic City casino dispute began in 2007, when United Auto Workers held an event with federal and state lawmakers saying that the union had majority support at the casino. The workers then voted 324 to 149 to join the union.

Trump asked for the election results to be discounted, saying the press conference had influenced the workers to join. Under NLRB precedent, any events or acts that make it seem the NLRB was biased could invalidate an election.

The NLRB rejected the notion that the election was biased, so the company brought the case before the appeals court that Kavanaugh sat on.

The report emerges as Democrats have launched an investigation into Kavanaugh's extensive paper trail, which lawmakers have estimated comprises a million pages.

Democrats have decried Kavanaugh's record on issues including immigration, abortion and impeaching a sitting president.

Kavanaugh worked for Kenneth Starr, the independent counsel who investigated former President Clinton. He once argued that a president could be impeached for lying to his staff or misleading the public.

He later recanted this stance after observing the discord caused by Clinton's impeachment, saying presidents should not be indicted or distracted by investigations while holding the office.

These views are likely to be explored heavily by senators during Kavanaugh's confirmation proceedings given the ongoing investigation by special counsel Robert Mueller into Russia's election meddling and possible Trump ties to the Kremlin.