TROY — Rensselaer County Court Judge Patrick J. McGrath announced Tuesday he is running against incumbent state Supreme Court Justice Anthony J. Carpinello.

McGrath, 55, a Democrat, made the announcement from the steps of the Rensselaer County Courthouse.

“I’ve decided to run because I’ve been on the bench for 23 years and the Supreme Court positions don’t come along very often and I thought it was now or never.”

Carpinello said he “welcomed the new entry to the race” and promised a vigorous campaign. He said there is a clear difference in the level of experience between him and McGrath.

McGrath said he would apply the same principles as a Supreme Court judge that he uses as a Rensselaer County Court judge.

“It is a matter of applying the same work ethic. I always believed in working hard and if you need to try a case, try it, and don’t procrastinate.”

McGrath said he’s had a number of firsts on the bench:

The first judge in upstate New York to create a drug court (in November 1997) for nonviolent offenders addicted to drugs and alcohol.

The first judge in the state to uphold the constitutionality of Buster’s Law for the prevention of extreme cruelty to animals.

The first judge in Rensselaer County to do a double jury murder trial — a single trial for two co-defendants with two juries — in 1996.

McGrath was first elected to Rensselaer County Court in 1994 and re-elected in 2004. Since 2006, he has been an acting Supreme Court justice.

Carpinello, 59, a Republican, announced earlier this year he would be seeking another 14-year term.

He is assigned to the Appellate Division but has to run for his Supreme Court seat to retain the appointment.

Carpinello serves in the Third Judicial District, which covers Albany, Rensselaer, Ulster, Columbia, Greene, Schoharie and Sullivan counties.

The retirement age for justices is 70, but a judge can apply to serve up to three two-year extensions.

Carpinello was appointed to the Third Department in June 1996. A native of East Greenbush, he graduated from Union College in 1970 and from Albany Law School in 1973.

He was elected to the Supreme Court in 1994 after serving two years as an East Greenbush town justice. Prior to that, he was a Rensselaer County legislator for eight years and an East Greenbush town councilman for seven years.

Carpinello was a law clerk for the 3rd Department from 1973 to 1974. Upon completion of his clerkship, he entered private practice in Albany where he specialized in commercial litigation for 20 years.