(CNN) Sen. Kamala Harris' entry into the 2020 presidential race is a continuation of what was already a historical year for women in the Democratic primary.

With fellow Democratic Sens. Kirsten Gillibrand and Elizabeth Warren having already formed exploratory committees and Rep. Tulsi Gabbard also in the race, 2020 features more female members of Congress running for a party's presidential nomination at the same time than ever before. And more could come, with Sen. Amy Klobuchar potentially joining the fray.

Women's pivotal role in Democratic politics has never been more evident, with multiple women from the Democratic Party likely to take the plunge into the primary, each with her own unique appeal to voters.

None of these women are at the top of the polls right now, though. All of them, however, are either at the top of our 2020 power rankings (Harris) or at least in the top 10.

What's going on? The current or potential Democratic candidates aren't well known right now.

About a third of Democrats couldn't form an opinion of Warren in a CNN national poll taken late last year. A majority hadn't formed an opinion of Harris or Klobuchar. A majority couldn't form an opinion of Gillibrand in a Quinnipiac University poll conducted in December.

Around 90% of Democrats have an opinion of the two candidates at the top of the polls, former Vice President Joe Biden and Vermont Sen. Bernie Sanders. I'm not sure that can hold as we get later into the primary process.

But once the women become better known, it's important to remember that female voters hold a powerful role in Democratic politics and were intent on choosing women as candidates in the most recent election cycles.

Women candidates dominated in 2016 and 2018 Democratic primaries. Hillary Clinton won the 2016 Democratic presidential nomination. Over 50% of women who ran in Democratic House primaries won in 2018. In fact, more women were nominated in Democratic House primaries than ever before.

It's not just that women are winning. It seems that they are winning in part because Democratic voters want to vote for women. A CBS News poll taken in 2015 found that when Clinton voters were asked during the primary to give their most important reason for backing her, the second most popular answer was "it's time for a woman president." A FiveThirtyEight analysis found that even controlling for other factors, being a woman was one of the best indicators of whether a candidate won a 2018 congressional Democratic primary.

Indeed, Democratic women in particular seem to be voting for women candidates. Across the 27 caucuses and primaries in 2016 with an entrance or exit poll , Clinton beat Sanders by an average of over 20 points among women. She won women in 22 of the states and lost women in only four states. Sanders won men in a majority of contests. The more than 20-point gender gap between them was about as large as was seen between Democrats and Republicans in the 2016 and 2018 general election.

The fact that women are interested in voting for women is important because they make up a disproportionate percentage of Democratic primary voters. In 2016 for example, women made up 58% of the primary vote in the average primary. They made up just 52% of the vote in the 2018 midterm election.

You can already see the strong potential of at least a few of the women candidates among Democratic activists. I've written previously how Harris is very strong among African-American Democratic activists and those based in the early primary states. This month, Warren won a straw poll among the Democratic liberal activists that largely makeup the Daily Kos community. She doubled Bernie Sanders' percentage of the vote, even though Sanders won every straw poll taken in the 2016 campaign

Now activist interviews and straw polls such as these aren't scientific and may not at all be predictive. They do, though, give us a window into how those who most closely follow politics are thinking.

Democratic voters look like they may want a woman to take on the man in the White House.

UPDATE: This story has been updated following Sen. Kamala Harris' entry into the 2020 race.