WASHINGTON — Long before President Trump nominated him for the Supreme Court on Monday, Judge Brett M. Kavanaugh had already made a name for himself as an influential conservative critic of sweeping environmental regulations.

During his 12 years on the United States Court of Appeals for the District of Columbia Circuit, often regarded as the nation’s second-most powerful court, Judge Kavanaugh voted in a number of high-profile cases to limit Environmental Protection Agency rules involving issues like climate change and air pollution. In two key instances, his arguments were later embraced by the Supreme Court.

His legal philosophy was clear: In the absence of explicit instructions from Congress, any far-reaching effort by the E.P.A. to tackle environmental problems should be met with deep skepticism by the courts. That philosophy often put him sharply at odds with the Obama administration, which sought to harness older environmental laws to deal with newer challenges like global warming.

“It’s a neutral principle, although the effect isn’t always neutral,” Richard J. Lazarus, a law professor at Harvard, said. “Congress stopped making clean air laws after 1990, so the E.P.A. has to work with increasingly tenuous statutory language. In effect, his approach to environmental law would make it harder to address current problems so long as Congress remains out of the lawmaking business.”