While it’s unquestionably true that the National Republican Senatorial Committee has few offensive opportunities in 2008 and is looking for states where it might put Democratic seats into play, the existing evidence simply isn’t compelling that the committee should spend even a penny of its very limited resources in the Garden State.

If history is any guide, and it should be, New Jersey has become bluer over the past 20 years. The last Republican Senate victory in the state was in 1972, when moderate Clifford Case won a fourth term. The last GOP presidential victory was in 1988.

This cycle, the alleged evidence of Lautenberg’s weakness comes from an Eagleton Institute poll conducted in early August. That survey showed Lautenberg with ID ratings of 38 percent favorable/24 percent unfavorable, and with job performance ratings that were worse, at 37 percent approve/32 percent disapprove.

By traditional standards, the Senator’s “re-elect” (“Thinking about the job that Lautenberg has done as U.S. Senator, do you think he deserves to be re-elected, or do you think it’s time for a change?”) was horrendous: 24 percent said he deserves to be re-elected, and 61 percent responded that it’s time for a change.

The first problem with using these poll numbers to conclude that Lautenberg is at significant risk is that New Jersey poll numbers almost always are deceiving. Incumbents invariably start their re-election campaigns with mediocre survey numbers because many state voters get much of their media from New York City or Philadelphia and aren’t especially attuned to the activities of their own Senators.

In May of last year, only 20 percent of respondents in a Quinnipiac University poll said they had a favorable view of New Jersey Sen. Bob Menendez (D), who had been appointed to the Senate seat and was carrying plenty of baggage during his first Senate race. Only 34 percent said they approved of Menendez’s job performance.

When matched against his Republican challenger, Tom Kean Jr., Menendez was leading by only 6 points and was at just 40 percent of the vote, a dangerous place to be for any incumbent. Other polls during the first six months of the year showed Menendez actually trailing Kean.

In November, Menendez won by 9 points, 53 percent to 44 percent. And that was the best Republican showing in a New Jersey Senate election since 1994, the Republican tsunami year when challenger Chuck Haytaian drew 47 percent of the vote against Lautenberg.

Lautenberg’s “re-elect” question is particularly misleading. Since voters hold Congress in such low regard and think the country is headed off on the wrong track, it isn’t surprising that they say it’s “time for a change” rather than that Lautenberg deserves to be re-elected. Since 36 percent of registered voters said they either had not heard of Lautenberg or had no opinion of him, it is easy for them to opt for change over continuity.

It’s not unreasonable to wonder whether Lautenberg’s age could be a problem for him, and the Eagleton survey asked split-sample questions about it. But again, the results are not exactly what they seem.

Half the sample was told that Lautenberg, the third-oldest member of the Senate, would be 84 years old at the start of his next term, while the other half was told that he would be 90 years old at the end of his term. Not surprisingly (and quite logically), more than six in 10 respondents said that he would not “be able to represent New Jersey effectively.”

The only problem for Republicans is that the Eagleton survey question is, in all likelihood, not predictive and, like too many poll questions, misleading.

The age questions isolate a single factor, but that’s not the way campaigns or elections work, or the way voters make their decisions. There are multiple messages going back and forth throughout a campaign, and in 2008, partisanship and the parties’ images, Iraq, George W. Bush, health care and “change” are likely going to be more important than Frank Lautenberg’s age.

Moreover, there is more than enough evidence that voters will re-elect older candidates, as long as they don’t seem out of touch or act in such a way as to raise fundamental questions about their abilities. West Virginia voters just re-elected increasingly frail Sen. Robert Byrd (D) when he was just shy of his 89th birthday, while Hawaii voters re-elected Sen. Daniel Akaka (D) at age 82. South Carolina voters re-elected Sen. Strom Thurmond (R) when he was over 90 years old and clearly unable to perform his duties independently.

Lautenberg’s age could become an issue, but it certainly is not guaranteed to become one or to threaten his re-election prospects, the Eagleton survey notwithstanding.

Finally, the national GOP’s brand is badly damaged and the Garden State Republican Party’s own vital signs are not good. Republicans have a very thin bench in the state, and it’s far from clear that they can find a top-tier Senate nominee next year.

We won’t know exactly where this race stands for months — until Republicans have a nominee and we see how the Iraq War stands. But whatever Lautenberg’s present or future vulnerabilities, he’s a Democrat running in a state and national political environment that favors Democrats. That gives Republicans no reason for even a shred of optimism.

Stuart Rothenberg is editor of the Rothenberg Political Report.