"This is all unprecedented," said Robert Williams, a Rutgers-Camden law professor who is an expert on the Supreme Court.
With a pair of seats open, the normally seven-member court would be short-staffed, and experts say its decisions may not carry the same weight in setting legal precedent.
The chief justice, according to the state constitution, may elevate the most senior appellate court judge to the high court for a period of time, or even for one case. Though only five are needed for a quorum, justices regularly recuse themselves on cases due to conflicts of interest, which requires an additional jurist to be called in.
Appellate court judge Dorothea O'C. Wefing is temporarily filling one vacancy now. But in October, a month after the court returns to session, she faces the mandatory retirement age of 70.
After Wefing, next in line to sit on the court is Judge Ariel Rodriguez, reportedly a Republican. If the chief justice chooses to temporarily fill the second seat, it would go to Judge Mary Catherine Cuff, who a source says is a Democrat.
Christie could make the political calculation that going with six justices, including Rodriguez as a short-term fill-in, might be better than nominating a Democrat as a permanent justice, which Democratic legislators say he is obligated to do to ensure balance on the bench.
The makeup of the court is crucial to the success of Christie's agenda, especially as cases may soon be heard on issues including affordable-housing mandates and education spending in poor districts.
It is gay marriage, however, that has dominated discussion in recent days. Christie recently vetoed a bill that would have legalized gay marriage, a cause Harris has championed in the past. In 2009, he wrote a letter to his state senator advocating for passage of a bill that would have allowed same-sex marriage. At the time, Harris was a councilman in Chatham, Morris County. He is now mayor.
Due to that proactive role while serving as a public official, Harris has said he would recuse himself if a case requiring to decide the constitutionality of same-sex marriage came before him as a Supreme Court justice, Christie explained Wednesday at a Statehouse news conference. Such a case is now pending in the courts.
"It makes no sense whatsoever," responded Sen. Raymond Lesniak (D., Union), a judiciary committee member who plans to vote against Harris.
"Advocating for an issue is immaterial to [deciding] the constitutionality of the issue. It just proves to me that Mr. Harris would not be an independent thinker on the Supreme Court. . . . I wouldn't be voting for Bruce Harris on the Supreme Court - I'd be voting for Chris Christie."
Christie rejected that notion, and said recusals were common.
"I think these are folks who are just looking for an excuse to vote against a Republican on the Supreme Court," he said.
Much has been made about the unwritten rules regarding political balance on the court, with governors making nominations that ensure there are no more than four members of one party on the bench.
Because of arguments over Supreme Court Justice Jaynee LaVecchia's political leanings, however, Democrats and Christie don't even agree on how many Republicans are on the court. So Christie rejects the protocol that he must appoint a Democrat.
Williams, the law professor, said the unusual politicizing of the high court began in 2010, when Christie broke precedent and decided not to grant tenure to Justice John Wallace, a Democrat and the only African American on the bench.
In March, the Democratic-controlled Senate judiciary committee also broke precedent - by not confirming Phillip Kwon, a high-ranking official at the state Attorney General's Office who was Christie's nominee for the first of open seats. Though now registered as an independent, he had been a registered Republican when he lived in New York.
It was the first time either action had occurred since the current state constitution was adopted 65 years ago.
"What we have now is a whole new political context surrounding the court," Williams said.
Beyond his political leanings, Democrats are likely to question Harris on Thursday about his lack of courtroom experience. As a finance attorney, Harris handles complex business transactions, and he has never tried a case.
"I think when you hear Bruce Harris tomorrow, objective people are going to be incredibly impressed," Christie said Wednesday. "This is a thoughtful, experienced, soft-spoken, interesting man who I think will bring an incredible perspective to the Supreme Court."
Harris has a sense of what he's in for. In March, while Senate judiciary committee members grilled Kwon about his political affiliations and a federal civil case involving his mother's liquor store, Harris sat in the front row. Harris is in a long-term relationship and was accompanied by his partner.
After nine hours of testimony, the committee voted not to move Kwon's nomination to the full Senate, with just one Democrat joining Republicans in objecting.
Asked Wednesday whether he would consider appointing a Democrat - or maybe no one - to the vacant seats in the event that Harris were rejected, Christie said he wouldn't get into hypotheticals.
But if Democrats insist he must appoint a member of their party to preserve balance, he said, then "we're headed for a stalemate."
Contact Matt Katz at 609-217-8355, firstname.lastname@example.org, or follow on Twitter @mattkatz00. Read his blog, "Christie Chronicles," at www.philly.com/ChristieChronicles