New Jersey Gov. Chris Christie (R-NJ) is almost certainly going to appoint a Republican for late Sen. Frank Lautenberg's seat. (AP Photo/Julio Cortez)

With Sen. Frank Lautenberg's (D-N.J.) passing, attention turns to Gov. Chris Christie (R), who will likely appoint a successor in advance of a special election either before this November's gubernatorial election, coinciding with that election, or in 2014. So will Christie burnish the bipartisan images he earned by working closely with President Obama after Hurricane Sandy, and appoint a Democrat to the seat? Or will he appoint a Republican to keep the party faithful happen, and maybe enable a run for national office later on?

The latter. I put the odds at around 95.6 percent, 88 percent if I'm being conservative.

Since the 80th Congress started on Jan. 3, 1947, a total of 93 senators have died or resigned from office, excluding those who resigned early to give their successors a seniority boost; I compiled a full list here. Of those, 25 were of a different party than their state's governor. Presumably, there are so many fewer of these cases because senators are reluctant to resign when the statehouse is in the other party's hands. In 22 of those 25 cases, the governor proceeded to appoint a member of his own party rather than someone from the party of the resigning or deceased party.

Democratic and Republican governors both do it, after both resignations and deaths. When Sen. Robert F. Kennedy (D-N.Y.) was assassinated in 1968, Gov. Nelson Rockefeller (R) picked Rep. Charles Goodell (R) to fill the seat, rather than keep it in Democratic hands. When Sen. William Saxbe (R-Ohio) resigned to become Attorney General in 1974, Gov. Jack Gilligan (D) appointed Howard Metzenbaum (D) to take his place. It's just how the appointments racket usually works.

But what about the three cases when a governor appointed someone from the departing senator's party, even though it's the opposite one from the governor? The most recent time this happened was in 2007, when Gov. Dave Freudenthal (D-Wyo.) appointed John Barrasso (R) to succeed Sen. Craig Thomas (R), who had died of leukemia. But that's because Wyoming law requires the governor to appoint someone of the same party as the previous senator. The Republican State Central Committee (or the corresponding Democratic committee, if a Democratic Senator dies) sends the governor a list of three candidates, from whom he chooses one.

The second most recent came on Dec. 30, 1976, when, following the death of Sen. Philip Hart (D-Mich.), Gov. William Milliken (R) appointed Rep. Donald Riegle (D) But Riegle had just won an election for Hart's seat, and was set to take office on Jan. 3. Giving him the extra four days in office was basically a formality. Appointing a Republican for such a short period would have been pointless.

The only case of a non-coerced cross-party appointment since World War II was in March 1960, when Sen. Richard Neuberger (D-Ore.) died and Gov. Mark Hatfield (R) appointed Hall Lusk (D) to hold the seat until an election was held in November. Neuberger's widow won the seat, and would in turn be succeeded by Hatfield in 1966. Hatfield was a somewhat unorthodox Republican, to say the least; he would distinguish himself in the Senate as a leading opponent of the Vietnam and Gulf wars, a proponent of a nuclear freeze, and an opponent of school prayer and the death penalty.

So excluding the Riegle and Barrasso cases, governors crossed the aisle for appointments in one out of 23 cases where the departing senator was of the opposing party; 95.6 percent of the time, they pick from their own team. If we want to be really generous and include Riegle and Barrasso, they do so 88 percent of the time. Either way, the odds that Christie picks a Republican for the seat are pretty overwhelming.

Update: Be sure to read Boris Shor on the ideologies of Christie's potential picks. His guess is that the pick will vote similarly to Olympia Snowe, Susan Collins, or Scott Brown.