Maybe make it the law that those who serve can own a gun, vote and drink at 18.
It was done in the 70s then eroded over time. 18 yr olds could vote in federal elections, buy beer at the px, and buy long guns. you had to be 21 to buy a pistol. if you were old enough to be drafted, you enjoyed the rights of citizenship. When the draft went away, the laws changed. In Florida in the 70’s I could buy a drink at a bar at age 18. We stopped treating 18,19 and 20 yr olds as adults, and the nanny state surged ahead. Of course the education system stopped teaching life skills, and instead taught them to take out loans to get more education in how to live in a fantasy world.