Democratic strategists working on races across the state said in interviews that they have seen a remarkable decline in support for Menendez as his Republican opponent — former pharmaceutical executive Bob Hugin — poured $36 million of his own wealth into his campaign. Hugin has used much of the money to run a seemingly endless stream of negative campaign ads. Even as public opinion polls show the senator up by double digits, some insiders say a post-summer boost, hoped for by team Menendez, never arrived.

Hugin’s relentless attacks, which took a dark turn the last three weeks, have chipped away at the scandal-scarred senator’s standing with suburban voters and women, some strategists said. Menendez, running in a state that has 900,000 more registered Democrats than Republicans, is now struggling to hold on to areas where he should have massive support, some said. In several competitive congressional districts, internal polls show votes for Menendez running far behind support for a generic Democrat, one strategist said.

As Menendez’s aides insists they’re “confident” he’ll win, some allies are openly admitting things may not turn out as planned, saying the massive advertising campaign on the other side has been difficult to overcome.