RALEIGH - After years of speculation, former Secretary of State Hillary Clinton announced she is running for president. And according to Tom Jensen, director of Public Policy Polling, her numbers against Republican challengers have dropped in North Carolina since the scandal surrounding her email account.

"A month ago, when we did our big North Carolina poll, we found that Hillary Clinton, on average, over the Republicans," Jensen says. "Now we find that, on average, she has a small deficit."

Jensen says this difference shows that North Carolina is a toss-up state in the 2016 national election.

While three Republicans have already entered the race for president, one of the biggest names has yet to announce his candidacy. Wisconsin Gov. Scott Walker has a history of conservative governing and has won repeatedly in a Democratic state. Jensen says this makes him an ideal nominee for Republicans.

"There's this debate that's ongoing in the Republican Party: do we want to nominate somebody who's a perfect conservative or do we want to nominate somebody who can actually win a general election against a Democrat?" Jensen says. "Walker has this message he can get across to voters that, with him, they don't have to choose."

Now that the 2016 presidential election is officially underway, opponents of Hillary Clinton are likening her to President Barack Obama. Jensen says this is an effective strategy in North Carolina.

"If Republicans effectively make the election a referendum on a third Obama term, they'll win because people are not that happy with Obama," he says.

Jensen says the likely nominees will be Clinton and Walker, but he says, out of the Republican candidates who have announced so far, Florida Sen. Marco Rubio will be formidable because, when polling, he is one of the most well liked Republicans in the country.

"As candidates inevitably falter over the course of the year, Rubio is really well positioned to pick up support as other candidates see their support fall," he says.

Of the other Republican candidates, Jensen says Kentucky Sen. Rand Paul is not well liked but Texas Sen. Ted Cruz is seeing his support rise rapidly. Jensen acknowledged that most pundits believe former Florida Gov. Jeb Bush will be the nominee, but Jensen says Bush's popularity with conservatives is too low.

It's clear the Republican field is full of a diverse array of candidates, but for Democrats, so far Clinton is the only candidate. Jensen says this is in line with many North Carolina Democrats.

"At the end of the day, not that many people want somebody else," he says.

Clinton is the only woman in the race so far and would be the first female nominee of a major party in a presidential election. Jensen says, when polling North Carolinians, 80 percent of respondents say gender does not affect their election decisions. But Jensen says he doesn't believe them.

"We think a lot of people think it's the right thing to say -- that Hillary Clinton's gender is totally irrelevant," he says. "But I think the reality is there's a decent number of voters who consider her gender a big positive and there's probably also a decent number of voters who consider her gender a big negative."

In the 2008 Democratic primary, Obama beat Clinton by more than 10 points in North Carolina.