PHILADELPHIA, Pennsylvania (CNN) -- Maria Wing is a lawyer in Philadelphia, Pennsylvania. She's 28 years old, single and in debt.
Pennsylvania attorney Maria Wing, 28, says it's becoming increasingly difficult to make it on one income.
She and thousands of other women like her could prove key in Tuesday's Democratic Pennsylvania primary. Single women overwhelmingly vote Democratic and in Pennsylvania one in four voters is a single woman, according to the "Women's Voices. Women Vote Action Fund," a group trying to mobilize the nation's women voters.
"Unmarried women will be to progressives what evangelicals were to conservatives. And, their participation rate and their policy agenda will be heard and will determine the future of this country," said Page Gardner, president of the WVWV Action Fund.
Gardner's group polled 1,000 unmarried women nationwide last month and found 58 percent of single women identify themselves as Democrats, compared to 18 percent as Republicans. Their support is almost evenly split between Sens. Obama and Clinton, favoring Clinton slightly, 50 to 48 percent.
Research by WVWV shows unmarried women with an average income of $30,000 or less, are the ultimate economy voters. They care about real-life economic needs such as healthcare, childcare, raising the minimum wage and equal pay.
Married women care about similar issues but single women have more at stake, Gardner said. She said unmarried women earn less and are three times more likely to lack health coverage. Also, 20 percent of unmarried women are also single moms and economic insecurities drive their vote.
"These women are economically stretched," Gardner said, "The economic gap between married and unmarried women really drives many of the political differences as well as the policy differences."
In Pennsylvania, according to United States Census data, 44 percent of unmarried women struggle with a household income of less than $30,000, compared to 14 percent of their married counterparts. Moreover, while 87 percent of married Pennsylvania women have private health care coverage; the number drops to 66 percent for unmarried women. Additionally, unmarried women make 56 cents on the dollar compared to men. Married women earn 77 cents on the dollar.
Like many Americans, the economy is the No. 1 issue for Wing, the Pennsylvania lawyer.
"We are on our own; [its] not like I have a husband or someone to augment my income should something happen with my job. I certainly can't ask my parents for anything," she said.
Wing is a first-time homeowner, with a very different take on the economy than many of her married girlfriends.
"My friends who are working and have their husbands, they're like, 'Oh, you know it'll shake out.' They worry about their 401k's, whether or not stocks are going up," said Wing. "I'm like, 'Dude, I'm worried that if the market keeps slipping' ... I can't help but think, 'Oh God, what if I lost my job?' "
Until recently, single women had been largely ignored by candidates and disengaged from the political process. In fact, in 2004, nearly 1 million unmarried women in Pennsylvania stayed home on Election Day, according to Women's Voices, Women Vote Action Fund. But in 2008, single women are a force to be reckoned with.
Political experts say if they continue to mobilize, these women could have a big influence on the election of the next president. Already this year, the presence of unmarried women at primaries has reached historic levels.
It became clear something had changed earlier this year in Iowa, where unmarried women accounted for 26 percent of Democratic caucus-goers -- though they represented only 22 percent of all registered voters. In New Hampshire, on average only one of nine unmarried women in the Democratic primary was an unregistered voter the day before the primary; in the Republican contest one of 13 was an unregistered voter the day before.
On every primary election day since, unmarried women voters have set records in turnout. Overall, they made up 26 percent of the electorate in the February 5 Democratic primaries where marital status was asked -- a number which exceeds their share of registered voters in these states. In every state except three, unmarried women made up a larger proportion of the Democratic primary electorate than their current registration suggested. In fact, unmarried women supported the winner in 15 out of 16 states and proved crucial in Obama's narrow win in Missouri, as well as Clinton's hard-fought victories in California, Massachusetts and New Mexico.
Campaigns have aggressively hired single women and targeted them for votes.
"Finally there's someone out there who's saying, 'You have a say, you have a role in society,' " says Wing.
Wing has decided to support Barack Obama. She believes he will provide the economic stimulus package she feels the country needs, and a tax code that benefits the middle class. One third of her income goes to paying off student loans, she says.
"After Uncle Sam gets paid and Fannie Mae gets paid and housing expenses get paid, mama only has a couple hundred dollars to go out," said Wing.
"I'm still driving my beat up Sentra from law school."
Gardner warns this growing bloc of voters can't be overlooked.
"If the candidates ignore these women and don't pay attention to what their policy agenda is, they will suffer at the polls" said Gardner. E-mail to a friend