MADISON, Wis. (AP) — Democrats know who their voters are. They just have to figure out how to get them to the polls in November — and that's where the puppies come in.

Students returning to the University of Wisconsin-Madison campus this summer were greeted by therapy dogs for petting. Those lured by the chance to ruffle a dog's ears were then asked to register to vote — a "Pups to the Polls" gimmick that was just one of several similar events being staged in 11 battleground states by the liberal group NextGen America.

Young people tend to vote for Democrats, but they also tend stay away during midterm elections. It's a perennial frustration for the party — one they are trying to overcome as they seek to take control of Congress.

NextGen America, formed by billionaire activist Tom Steyer, hopes to be a game changer. Steyer is investing more than $30 million in what's believed to be the largest voter engagement effort of its kind in U.S. history.

The push to register and get pledges from college students to vote is focusing on states such as Wisconsin, Virginia, California and North Carolina with competitive races for Congress, U.S. Senate and other offices.

NextGen sees young voters such as Kellen Sharp as key to flipping targeted seats from red to blue.

"The outcome of this election definitely affects us," said Sharp, an 18-year-old freshman from Milwaukee who stopped to register during the dog event the week before classes started. "I'm just excited to have a voice and say something."

A poll this summer by the Associated Press-NORC Center for Public Affairs Research and MTV found that most Americans ages 15 to 34 think voting in the midterm elections gives their generation some say about how the government is run. The poll found young people eager to vote for someone who shared their political views on issues such as health care and immigration policy. They expressed far less excitement about voting for a candidate described as a lifelong politician.

"If we all vote, we can make a change," said 20-year-old Grace Austin, who stopped to pet the dogs at the Wisconsin event and wound up registering to vote.

Austin and other college students who registered said they feel like their friends are more interested in politics than ever before — boosting hopes of Democrats trying to reverse the trend of declining youth participation in midterm elections.

"We want them to know they need to show up and when they do, we will win," said NextGen's Wisconsin director George Olufosoye. "We want them to know they have power."

They certainly have the numbers.

Since the last midterm election in 2014, 15 million post-millennials — those between the ages of 18 and 21 — have become eligible to vote. But while Generation X, millennials and post-millennials make up the majority of voting-eligible adults nationwide, they are not expected to cast the most votes in November.

In the 2014 midterm, they cast 21 million fewer votes than voters over age 54, according to an analysis by the Pew Research Center. Turnout among 18- to 24-year-olds hit a 40-year low in 2014, bottoming out at 17.1 percent, according to an analysis by the Center for Information and Research on Civic Learning and Engagement, or CIRCLE, at Tufts University.

NextGen points to higher voter turnout on the University of Wisconsin campus for a spring state Supreme Court election won by a liberal, and spikes in turnout in other targeted races, to argue that their push to register 122,000 young people to vote is bearing fruit.

"We're trying really hard to have this be much more of an infrastructure, organizational thing than a two-month campaign," NextGen founder Tom Steyer said in an interview. "We're trying to get the broadest possible democracy, the biggest representation."

More media coverage of competitive races, combined with energy from the March for Our Lives movement that seeks stricter gun laws, has empowered young voters and made them "feel like it's time to have their voice heard about what happens to their generation," said Kei Kawashima-Ginsberg, director of CIRCLE.

That's what NextGen hopes. It has nearly 800 organizers on 421 college campuses in Wisconsin, Arizona, California, Florida, Iowa, Michigan, Nevada, New Hampshire, North Carolina, Pennsylvania and Virginia. In Wisconsin alone, NextGen has 27 full-time workers and 40 student fellows registering voters on 26 campuses.

Republicans recognize the power that motivating young voters could have for Democrats, but they're skeptical that participation will increase much. In Wisconsin, Republicans have been targeting college voters for years.

"Wisconsin Republicans win by connecting with voters directly where they are — and young voters are no different when it comes to that strategy," said Wisconsin Republican Party spokesman Alec Zimmerman.

Wisconsin has two of the nation's competitive and closely watched races. Democratic Sen. Tammy Baldwin is being challenged by GOP state Sen. Leah Vukmir, while Republican Gov. Scott Walker faces a challenge from Democratic state schools chief Tony Evers. Polls show the races to be a dead heat — just the kind of competitive elections research shows excite younger voters.

"I've never seen anything like this," said NextGen worker and 2016 University of Wisconsin graduate Joe Waldman. "I've never seen the energy, passion and activism there is now."