Republican Senate pickup opportunities have largely dwindled to a handful of heavily Republican states, with the possible addition of Florida. Some analysts, however, are interested in the New Jersey Senate race, where some polls show scandal-tarred incumbent Robert Menendez against businessman Bob Hugin. Menendez leads by six points in the RCP Average, but is overall at 47 percent.  Moreover, only one poll has shown him with a lead in excess of six points since April.  Could Menendez provide the GOP with another pickup opportunity?

I am skeptical.  The problem for Republicans is that we have two fairly recent precedents for such a situation in New Jersey, neither of which ended well for them.  The first occurred in 2006, the year Menendez was first elected to the Senate.  Democrat Jon Corzine had been elected governor of the Garden State in 2005. He appointed Rep. Menendez to the open seat that he had left vacant.  Menendez was already touched by scandal and looked vulnerable at the beginning of the next cycle. Republicans nominated Tom Kean Jr., the son of a legendary governor and a moderate who was seen as having a good chance of picking up the seat for the GOP.

Indeed, early polling confirmed this as a top-tier pickup opportunity. For most of the year the pair traded leads in polls; at one point in August and September, Kean lead or tied in seven straight polls.  But Kean’s last lead came in mid-October; Menendez led or tied in every poll down the stretch. Kean’s problem was that he was in a Democratic state and had difficulty breaking 45 percent in the polls. The undecided voters that year almost certainly disapproved of President Bush, and Kean was going to have to persuade them to pull the lever for him even as the country was becoming more polarized.  He ended up getting 44 percent of the vote.

The second example comes in 2002.  In a very different political environment, scandal-tarred Sen. Bob Torricelli found himself in dire straits against Republican businessman Doug Forrester.  He trailed Forrester in the polls in a year where President Bush was quite popular.  About a month before the election, he dropped out of the race.  The Supreme Court of New Jersey allowed the Democratic Party to place former Sen. Frank Lautenberg on the ballot.  Lautenberg went on to win against Forrester.

What do these examples tell us about New Jersey this year?  It suggests that it is an uphill climb for the Republican.  First, Menendez is in a bit stronger situation than the one he found himself in 12 years ago. He’s below 50 percent, but has a lead this time.  The Republican president is not quite as unpopular as Bush was in 2006, but he’s still unpopular.  We might suspect, then, that the undecided voters are Donald Trump disapprovers who are primed to vote against a Republican candidate.  Indeed, this might be what the recent Quinnipiac poll showing Menendez up by 11 points suggests. Hugin is roughly at his average, while Menendez appears to win over all the undecideds.

In the end, though, if Menendez were in serious trouble, Democrats would simply replace him, as they did Torricelli.  That he hasn’t been replaced suggests Democrats don’t really consider his situation dire. And if it becomes dire, we probably shouldn’t expect Menendez to see it through to the end.

Sean Trende is senior elections analyst for RealClearPolitics. He is a co-author of the 2014 Almanac of American Politics and author of . He can be reached at . Follow him on Twitter .