How are laws requiring gun buyers to be 21+ constitutional?

Question

Isn't anyone 18 or older guaranteed full constitutional rights? How can someone between 18 and 21 be denied the right to own a gun based on age?

Answer 1

Isn't anyone 18 or older guaranteed full constitutional rights?

No.

How can someone between 18 and 21 be denied the right to own a gun based on age?

The Second Amendment authorizes reasonable regulation of the right to own a gun (it contemplates a "well-regulated" militia).

Nothing in the U.S. Constitution states that age 18 is the age of majority for all purposes. The U.S. Constitution merely states that the right to vote in a federal election cannot be denied on the basis of an age older than age eighteen. (A U.S. state could let 14 year olds vote if it wanted to do so.)

But, many legal rights are limited to persons aged twenty-one or older (e.g. drinking, tobacco smoking, serving as an executor of a decedent's estate, etc.), or to some other age (e.g., age discrimination in employment laws start at age 40, legal discrimination for senior citizen oriented housing starts at age 55, eligibility to run for the U.S. House starts at age 25, for the U.S. Senate at age 30, and for the Presidency at age 35.)

Historically, until the Vietnam War, the age of majority for most (but not all) purposes in the United States was twenty-one years of age.

A majority of U.S. courts that have considered the issue have found that an age twenty-one restriction on the right to bear some or all arms is a reasonable regulation of the Second Amendment right that is constitutionally permitted, although there is a split of authority and one or two cases have reached the opposite conclusion.

Answer 2

This was most recently decided in NRA vs. BATFE in 2013. There were two basic reasons:

First, the Second Amendment can be seen as both providing an individual right and a collective right. The court found that age-based restrictions do not violate the individual right, because under 21 buyers can still purchase long guns under federal law, and they can still possess and use handguns under federal law (e.g. if someone buys it for them as a gift), so their individual right to self-defense is not seriously abridged. They also found that the collective right is not violated because an age-based restriction is not a blanket ban for an entire community.

Second, they rejected an equal protection claim under the 5th Amendment and found that age-based discrimination is permissible because age is not a strictly protected class, such as race, sex, or religion.

In constitutional law, the three review standards are strict scrutiny, intermediate scrutiny, and rational basis. On the first issue, the court found that the restriction of the Second Amendment had to pass the intermediate scrutiny test. This requires that the government demonstrate the law is "substantially related" to furthering an "important government interest." They found that the age-based restriction was substantially related to furthering the goal of reducing gun crime, and was therefore constitutional.

On the second issue, the court found that age-based discrimination only had to pass the rational basis test. The rational basis test is less strict than intermediate scrutiny, so it automatically passed.

The NRA filed for certiorari with the Supreme Court afterwards, and in 2014 the petition was denied. Thus the lower court ruling stands.

Reference

Full Text of Ruling