Republican presidential candidates often struggle to find success in the hostile Garden State, Dworkin said. New Jersey is dominated by two major media markets -- New York City in the north and Philadelphia in the south. With little chance of carrying New York, Republican presidential nominees often forgo heavy investment in the pricey New York City market, making a Republican victory in a New Jersey Senate race even less likely.
"Any Republican U.S. Senate candidate in New Jersey running in a presidential year isn't going to really have a strong top of the ticket to help him," Dworkin said.
Optimistic Republicans might point to Christie's continued popularity and impressive 2011 gubernatorial victory as evidence that things have changed for the GOP in the state. But Dworkin said Christie's success doesn't necessarily translate to Senate contenders. While Christie certainly has enhanced the Republican brand within the state, a Senate race presents unique challenges.
"You have to distinguish between running statewide for a Trenton office and statewide for a D.C. office," Dworkin said.
Polarizing issues - like support for Supreme Court nominees, abortion, and the Tea Party - come into play for Republicans running statewide for federal office in New Jersey.
Finally, Menendez's formidable political skills should not be overlooked. While Menedez's numbers may appear weak now, Tom Kean Jr. (R) and other GOP hopefuls still have an uphill race ahead. That much was evident in a Fairleigh Dickinson poll released Monday that showed Menendez holding double digit leads over all potential challengers so far.
"Bob Menendez is a very skilled and tough politician who is going to run a very strong, well-funded, well-organized race," Dworkin said. "It's going to be a very tough race for any Republican."