Republicans are increasingly optimistic about their chances to take out Sen. Robert Menendez, D-N.J., as their nominee Bob Hugin has turned what many expected to be a Democratic cakewalk into a close contest with two months to go before Election Day.

In just a few months, Hugin, a former pharmaceutical executive, has made this blue-state Senate race surprisingly competitive in a Democratic year. Since announcing in February, he has poured at least $15 million into the race, and promised upwards of $20 million, and has flooded the airwaves statewide unopposed from mid-May until Menendez went on the air on Tuesday.

That strategy paid off in the polls, as Quinnipiac and Gravis show him down by 6 and 2 points, respectively, in the only two surveys taken since the state's primary contests. An internal poll conducted by Hugin's campaign shows him in a neck-and-neck race against Menendez, which has given both national and state Republicans hope.

"I think he's our best chance in the last 40 years," said Rep. Tom MacArthur, R-N.J., of the possibility of Republicans winning a Senate seat in New Jersey. "He's a good man. He's really had an American dream kind of life ... It's going to be an ugly fight; it already is. But I think there couldn't be a starker contrast between those two men."

It's a tough election cycle for Republicans nationally, but Menendez faces issues at home stemming from the corruption charges he fought off in late January. He won his June primary with only 62 percent support against a virtual unknown opponent despite being backed by the state party machine.

According to the Quinnipiac poll, ethics has become a top issue for voters. Twenty-five percent name ethics as their most important issue, and 21 percent say it's taxes in the high-tax state of New Jersey.

Hugin has made made ethics a major campaign issue, but because he's new, 54 percent still haven't heard enough about him to form an opinion. The rest are split, as 24 percent have a favorable view of Hugin, while 20 percent disapprove.

Meanwhile, Menendez holds a 29 percent favorability rating and a 47 percent unfavorable rating. The same amount disapprove of his job, although 40 percent approve of his job in Washington. Nevertheless, Democrats remain bullish about Menendez's chances.

"I think Bob is in a remarkably favored position that he never would have anticipated six months ago or a year ago," said Jim McQueeny, a former top aide to the late Democratic Sen. Frank Lautenberg. "He got an opponent who's vulnerable because of the pharma background and an easy target. Drug company people today are probably ranked lower today than cable repair people."

"He probably drew the perfect person," McQueeny added.

Additionally, they are banking on anti-Republican sentiment both on the national and state level due to the marks left by President Trump and former Gov. Chris Christie, who many charge with leaving the party in ruins after his final years in office.

Democrats have also tried to lob ethics attacks back at Hugin over his tenure as executive chair of Celgene. They point out that he doubled the price of a vital cancer drug, and that Celgene settled cases for $280 million after pushing drugs that were not approved by the Food and Drug Administration.

But Republicans welcome the surprise charge by Hugin because it adds to the number of seats Democrats need to defend. Sen. Thom Tillis, R-N.C., co-chairman of the National Republican Senatorial Committee, admitted that he didn't expect the New Jersey race to become competitive months ago.

"If I'm on the other side of the aisle, I'm kind of worrying about what kind of bets their going to have to make to defend versus pick up [seats]," Tillis said.

Republicans are looking to a host of seats held in red states for them to keep their majority and possibly expand it, including in West Virginia, North Dakota, and Indiana.

Democrats remain cautiously optimistic that Menendez will ward this challenge off, and note that Hugin has been unable to overtake Menendez in public polling despite being on the air statewide for the past three months. They expect polling to bounce back in Menendez's favor after he returns serve on the airwaves in the coming weeks, but it is a race they are all watching closely.

"This will be a tough, tough election still ... While this is a tough fight for Bob, I've never met a tougher, more disciplined campaigner," said McQueeny, before quoting Lautenberg: "[I]n New Jersey ... politics is a bloodsport, and the objective is to have less of your blood in the sand than your opponents."