Ayanna Pressley’s first legislative proposal as a Massachusetts congresswoman was an amendment to lower the voting age for federal elections from 18 to 16. On March 7, the House of Representatives made short work of the measure, defeating it by a large bipartisan majority.

In her floor remarks before the roll call, Pressley claimed that 16- and 17-year-old kids are qualified to vote by virtue of the “wisdom” and “maturity” that comes from being alive and confronting the “challenges, hardships, and threats” of 2019. “Some have questioned the maturity of our youth,” she told her colleagues. “I don’t.” If that was her best argument for lowering the voting age, it’s no wonder 70 percent of House members weren’t persuaded.

Then again, if Pressley has such unquestioning faith in the maturity of high school sophomores, why seek merely to give them the vote? To be consistent, she should push as well to lower the legal drinking age to 16. And the minimum age for buying cigarettes, handguns, and recreational marijuana. And the age at which one can adopt a child. And at which a criminal offender is automatically prosecuted as an adult. Come to think of it, Pressley should also want to lower the age of enlistment in the military to 16, and to require everyone reaching that age to register with the Selective Service System. After all, if the wisdom and maturity of 16-year-olds qualifies them to vote, why shouldn’t it qualify them to be treated as adults in every other way?

The reason all these activities are legally barred to kids in their mid-teens is because, as almost all adults understand, the “maturity of our youth” is in fact highly questionable. Certainly there are some 16-year-olds who are thoughtful and astute, but as a general rule — and public policy relies on generalizations — maturity comes later. That’s a function not just of experience, but also of biology: Adult and teen brains operate differently. The prefrontal cortex, the part of the brain associated with rational judgment and awareness of long-term consequences, doesn’t fully develop until the mid-20s. Teens more often rely on the amygdala, the more emotional, primitive part of the brain. It isn’t from gratuitous animus that car-rental agencies make it difficult for young drivers to rent a vehicle. Or that the Constitution establishes 25 as the minimum age to be a member of Congress.

Of course, another reason that 16-year-olds are subject to so many restrictions that don’t apply to grown-ups is that they don’t know anything — or in any case, they don’t know enough to be trusted to make sound decisions about liquor, firearms, joining the Marines, and governing the United States. The ignorance of teens is practically a cliché. “If you go to any college campus and talk to the first thousand 18-year-olds you meet,” wrote Josh Gelernter for National Review in 2014, “you’ll find five who are qualified to vote and 800 who don’t know who Churchill was.”

In 1971, the 26th Amendment lowered the voting age nationwide from 21 to 18, largely on the strength of the claim that if 18-year-olds were old enough to be drafted — many young men were being called up and sent to Vietnam — they were old enough to be given the vote. The moral force of that argument couldn’t be denied, but let’s face it: The quality of American politics and governance wasn’t improved by letting 18-year-olds vote.

Like Pressley now, Senator Ted Kennedy then was sure that giving teens the vote would be a boon. “We will gain a group of enthusiastic, sensitive, idealistic and vigorous new voters,” Kennedy said at the time. He was wrong. Newly enfranchised young people immediately became the least engaged cohort, invariably turning out to vote at a lower rate than any other age group. Speculation about a “youth wave” revives every election season, but it never amounts to anything: Turnout among voters in their teens and early 20s always lags far behind turnout among their elders.

I don’t share the popular fetish for maximizing voter turnout, and have long argued that people who don’t have an interest in voting shouldn’t be hectored to do so. Nonetheless, if Pressley wants to increase the level of voter participation and involvement, I have a suggestion.

Instead of trying to lower the voting age, Boston’s new congresswoman should lead an effort to raise it. Let’s require Americans to wait until they are 25 before they can cast a ballot. That would immediately boost voter turnout, since participation in elections rises as the concerns of adulthood rise. The more likely people are to have jobs, to support themselves, to be married, to worry about schools or mortgages or taxes, the more likely they are to take an interest in how they are governed — and the more likely to show up on Election Day.

Pandering to children will do nothing to elevate our democracy. Restoring the link between democracy and adulthood, on the other hand, just might. Young people who join the military should immediately be entitled to vote; everyone else should have to wait until they turn 25. Keep Americans from the polls until their prefrontal cortex has finished growing. More mature voters might just mean more mature politics. Isn’t that an outcome worth pursuing?

(Jeff Jacoby is a columnist for The Boston Globe).