Judge Brett Kavanaugh, President Donald Trump’s nominee for the Supreme Court, has sat on the U.S. Court of Appeals for the District of Columbia Circuit since 2006. Here are summaries of some of his notable opinions:

HELLER v. DISTRICT OF COLUMBIA

In a pivotal 2011 Second Amendment case, Kavanaugh wrote a dissenting opinion when the D.C. Circuit Court upheld a District of Columbia ordinance banning most semi-automatic rifles.

Kavanaugh argued that the Second Amendment included the right to own semi-automatic rifles.

Kavanaugh wrote that the Supreme Court has found that handguns — “the vast majority of which today are semi-automatic” — are constitutionally protected.

“Semi-automatic rifles, like semi-automatic handguns, have not traditionally been banned and are in common use by law-abiding citizens for self-defense in the home, hunting, and other lawful uses,” he wrote.

Citing his upbringing and working life in the area, Kavanaugh said he was “acutely aware” of the area’s gun, drug and gang violence.

“But our task is to apply the Constitution and the precedents of the Supreme Court, regardless of whether the result is one we agree with as a matter of first principles or policy,” he wrote.

GARZA v. HARGAN

In 2017, Kavanaugh was involved in a case that touched on the hot-button issues of abortion and immigration.

The dispute was over whether a teenager who was in the U.S. illegally could be released from immigration custody to obtain an abortion. After a federal judge found she could be released, Kavanaugh wrote a panel decision blocking the abortion for up to 10 more days to give the government time to find the 17-year-old an immigration sponsor. The full appeals court overturned that ruling.

In a stinging dissent, Kavanaugh blasted the majority for an approach he called “radically inconsistent with 40 years of Supreme Court precedent.”

“The majority apparently thinks that the Government must allow unlawful immigrant minors to have an immediate abortion on demand,” Kavanaugh wrote.

He said requiring the government to assist the girl in obtaining an abortion would ignore the government’s “permissible interest in favoring fetal life, protecting the best interests of a minor, and refraining from facilitating abortion.”

PRIESTS FOR LIFE v. HHS

In 2015, Kavanaugh wrote a dissenting opinion from the appeals court’s denial of a full court rehearing of a ruling against a religious-liberty challenge to the Affordable Care Act’s contraceptive coverage mandate.

The law requires most employers to provide health insurance for their employees — including all Food and Drug Administration-approved contraceptives — or pay a significant fine to the government.

To be exempt from the monetary penalty, religious organizations need to submit a form to their insurer or the federal government. The insurer is required to continue to provide contraceptive coverage to the religious groups’ employees through separate funds provided by the insurer or the government.

Some religious organizations complained that submitting the form violates their religious beliefs because it made them complicit in providing coverage for contraceptives.

Kavanaugh wrote that the mandate infringed on the rights of religious organizations.

“When the Government forces someone to take an action contrary to his or her sincere religious belief (here, submitting the form) or else suffer a financial penalty (which here is huge), the Government has substantially burdened the individual’s exercise of religion. So it is in this case,” Kavanaugh wrote.

WHITE STALLION ENERGY CENTER LLC v. EPA

In this 2014 opinion, Kavanaugh argued that the Environmental Protection Agency must take monetary costs into consideration when deciding whether to regulate emissions from power plants.

The appeals court affirmed the emissions standard set by the EPA in 2012 for mercury and other pollutants from coal- and oil-fired electric utility steam generating units.

One of the key issues in the case was whether EPA was required to consider the costs imposed by the rule. The majority of the court agreed with the EPA that it did not have to consider the costs.

In his dissent, Kavanaugh wrote that it came as a “surprise” that the EPA did not consider costs.

“In my view, it is unreasonable for EPA to exclude considerations of costs in determining whether it is ‘appropriate’ to impose significant new regulations on electric utilities,” Kavanaugh wrote.

“To be sure, EPA could conclude that the benefits outweigh the costs. But the problem here is that EPA did not even consider the costs.”