The basic argument is that lowering the voting age (expanding suffrage) would empower young people to learn how to vote when they are still surrounded by their support network (friends, family, etc). We allow folks driver permits and work permits to learn other important life skills. Why not let them vote in state and local elections to learn the importance of their vote? It would also increase civic education in our schools by empowering teachers to help students navigate first-time voting (and have multiple opportunities!) 
 

Addressing Frequently Used Talking Points Against Lowering the Voting Age:

Young people will just vote how their parents tell them to.  

This was the same argument used against women when they were trying to obtain suffrage. Many people were opposed to women voting because many thought that women would just vote the way their husbands tell them too. That is far from the case because according to the Pew Research Center, women were 7% more likely to be left-leaning than men(the data includes men and women of all sexual orientations). 

But in the case of young people, many opponents of vote 16 will say “they will just vote the way their parents tell them to” but young people are more likely to lean left than older age groups, which means that young people are not afraid to push back with different beliefs. Also, it is illegal to force or coerce ANYBODY to vote a certain way. 

Young people don't pay taxes yet — why should they vote?

This was an argument that was used against suffrage for women before it became legal for white women to vote in 1920, and before it became legal for women to obtain their own bank accounts and credit card loans without a male cosigner in 1974. 

Many young people work in part-time jobs where their money will be taxed if they work for more than a year. Since many 16-17-year-olds work in a consistent part-time job and have taxes taken out of their paycheck, it is only fair to allow them to have a say and vote for what they think the government should spend their tax money on.

Young people don't know enough to vote

Young people are in fact, quite competent, many of them civically engaged with their peers around them within their community. Since 16 and 17 year olds are so close to being legal adults able to make their own big decisions, it’s important that we give them an opportunity to have a stake in what they want their adult future to be like by allowing them to vote. 

What about brain development? Aren't teens' brains underdeveloped?

According to the National Institute of Health, they say that brain development ends at 25 - do you know what that means? After 25, it is harder to form new neural pathways which are developed when you learn new skills. Since 16 and 17-year-olds are still in the process of brain development, it is the perfect time for them to experience voting for the first time and learning from that experience because it will encourage them to remain civically engaged throughout the rest of their life.