In a trend that adds a nice dose of fairness to election laws, 22 states now allow citizens who will be 18 years old on or before a general election to vote in their party’s corresponding primary or caucus. Illinois, for example, allows 17-year-olds who were born on or before Nov. 4, 1996, to register and cast ballots in this year’s March 18 party primary election, as the teens will be 18 and able to vote in the Nov. 4 general election.

Where 17-year-olds can vote in primaries and caucuses:

States that currently allow 17-year-olds [who will be 18 by the date of the general election in November] to vote in primaries and caucuses are: -Alaska–Connecticut–Hawaii–Illinois–Indiana–Iowa–Kansas–Kentucky–Maine–Maryland–Minnesota–Mississippi–Nebraska–Nevada–North Carolina–North Dakota–Ohio–Oregon–Virginia–Vermon–and Washington.

Of course, when things like this are done state-by-state, there are always some quirky, local variances. In Alaska, Kansas, North Dakota and Washington, 17-year-old Democrats may caucus, but 17-year-old Republicans cannot participate in their party’s caucus.

To check on your voting status in your state, go to Vote411.org

The rationale for “Suffrage at 17” is simple. Fair Vote, a voting-rights advocacy group, puts it this way:

A notable portion of citizens who have the right to vote in the general election in November currently do not have a voice in determining who will be on that general election ballot. Granting voting rights in primaries and caucuses to these 17-year-olds is only fair and will increase their political engagement through participation.

“Suffrage at 17” advocates say that one of the prime benefits of allowing 17-year-olds to vote in primaries is that it encourages civic engagement at an earlier age. Voting when young starts a lifetime habit, they contend. That’s good for political parties, too, goes the argument, because once someone has voted in a particular party’s contest, that young person may vote for that party for decades–if parties are important to you.

Opening up primary voting and caucus participation to 17-year-olds taps into a large market of potential new voters—a significant demographic. In 2008, there were more than four million 17-year-olds in America. Young eligible voters (18 to 29 year-olds) have traditionally voted at the lowest rates because they are not prepared for participation. Advocates say that the “Suffrage at 17” policy puts more young people on the voter rolls and prepares them to participate in the general election.

[As an aside, for some, the notion of “Suffrage at 17” doesn’t go far enough. A few years ago, a group of Massachusetts teens launched an initiative to lower the voting age to 17–for school-board and local elections. Their rationale was that school boards make decisions that directly affect teenagers, and that they should have a say in those elections. To me, that argument has some merit–and to those who worry about “immaturity” at the polls, I’d say that young people are no more likely to engage in irrational voting and immature behavior than older voters, who demonstrate a lot of stinkin’ thinkin’ at the polls during every election cycle.]

“Suffrage at 17” makes sense. It doesn’t do anything drastic, like officially lowering the voting age for everyone [we did that in 1971, when the legal voting age went from 21 to 18]. It’s logical–especially in a world where primaries and caucuses reign supreme in determining who will be on general-election ballots. And it’s a welcome example of a voting-rights expansion at a time when too many state legislatures are going in the opposite direction.

[By the way, we really need a whole new system for presidential primaries. Read more about this issue here.]