One of the biggest wild cards in the 2018 battle for the U.S. Senate may not be so wild after all. New Jersey Democratic Sen. Bob Menendez’s federal corruption trial ended in a hung jury last week. That leaves him free to run for reelection in 2018. Menendez could be retried, but many legal experts believe that a conviction is unlikely. Without that conviction, and absent major action following a Senate ethics investigation, Menendez is a clear favorite in 2018.

The case against an easy Menendez victory in the general election comes down to his current popularity — or lack thereof. An October Quinnipiac University survey put his approval rating at just 31 percent among New Jersey voters; 49 percent disapproved. Whether or not Menendez remains this unpopular following the lack of a conviction remains unclear. But any senator who has an approval rating of 31 percent should be in some danger of losing.

Yet, the Republicans who have emerged to challenge Menendez aren’t likely to strike much fear in his campaign. None has more than about $4,000 on-hand, according to the Federal Election Commission. Menendez has nearly $4 million. Ousting an incumbent senator — even an unpopular one — with no money is … difficult. That’s especially true for a Republican in blue New Jersey given how expensive New York and Philadelphia media markets are.

Why hasn’t a stronger challenger emerged given Menendez’s trial and weak approval numbers? It comes down to the fundamentals. There are just so many factors working in Menendez’s favor.

First, New Jersey is heavily Democratic. It’s 12 percentage points more Democratic-leaning than the nation as a whole, according to a weighted average of the last two presidential results. Second, 2018 is shaping up as a really Democratic-leaning election year. Nationally, voters currently favor congressional Democratic candidates over Republican candidates by 11 percentage points on the generic ballot.

So Menendez’s challenger will be running in a blue state in a blue year. A generic Democrat, in other words, probably starts out with about a 20-point edge in a 2018 New Jersey Senate race.

That Menendez is an incumbent also helps. The advantage of incumbency can vary by election, and, on average, it’s gotten smaller in recent years. But incumbents still usually do better than you’d expect given a state’s fundamentals. In 2012, for example, Menendez won reelection by nearly 20 percentage points. He did so when the national political environment was much less friendly to Democrats than it looks to be in 2018 — Democrats won the national House vote by 1 percentage point in 2012. That is, Menendez did about 6 points better than you’d expect a Democrat to do in New Jersey in 2012.

Combining what’s likely to be a strong Democratic national environment and the Democratic lean of New Jersey, one would expect a Democratic incumbent senator in New Jersey to start somewhere in the neighborhood of a 30-point favorite in 2018.

Menendez probably won’t win by 30 points. The scandal will almost certainly hurt him. It’s just unlikely to hurt him by enough to give a Republican that good of a chance. A paper from Nicholas Chad Long estimated that Senate incumbents from 1974 to 2008 involved in scandals lost an average of 12.6 percentage points off their reelection margin. In such a scenario, Menendez would still be forecasted to win by about 20 percentage points. Obviously, there’s a margin of error surrounding this estimate, but it would take a pretty big error for Menendez to lose given these fundamentals.

So Menendez, scandal notwithstanding, would be a general election favorite. There has, however, also been talk that a fellow Democrat might defeat him in the primary, before he ever gets to the general. Again, I’m skeptical.

The most well-known potential challenger, former U.S. Sen. Bob Torricelli, announced on Thursday that he would not run. No Democratic challenger has raised any money with the FEC. Menendez has also locked down the endorsements of pretty much every major Democratic political player in the state, including the incoming Democratic governor, Phil Murphy.

Democrats looking to take on Menendez may also be warned off by the polling. Menendez is still moderately popular with Democratic voters. The aforementioned Quinnipiac survey had his approval rating with Democrats at 45 percent; 27 percent disapproved. And again keep in mind, this polling was conducted before the jury failed to convict Menendez. It wouldn’t be surprising if his approval rating rose now, especially if the 28 percent of Democrats who were undecided before the hung jury move into the approval column post-trial.

Of course, nothing in politics is certain. Despite his approval rating with Democrats, for instance, there was also a note of caution in that Quinnipiac poll: Asked whether Menendez deserved to be reelected, 29 percent of Democrats said yes to 42 percent who said no.

So there might be an opening if anyone could find a formidable challenger to take advantage of it. That just doesn’t look likely to happen.

Instead, Menendez became a heavy favorite to win reelection when the jury came back hung on Thursday. The big questions are whether the government retries him and whether Menendez’s approval rating improves following the lack of a conviction. If his approval rating does rise, the chance of a strong challenger emerging is minimal. If his approval rating doesn’t recover or the government gives it another go, then there’s a higher chance that the fundamentals won’t hold.