Lawrence Mulqueen, 50, pleaded guilty to federal charges in exchange for an agreement from prosecutors to recommend a sentence of 12 to 18 months.
Authorities said Mulqueen, using a pseudonym, ranted online that he wanted to kill Senate Majority Leader Harry Reid, House Minority Leader Nancy Pelosi, Gov. Andrew Cuomo, New York City Mayor Michael Bloomberg, U.S. Sen. Charles Schumer, U.S. Rep. Nita Lowey and members of the Congressional Black Caucus.
Mulqueen was arrested in February when his landlady complained he was harassing her. Police said she tipped them about the Facebook page, which was under a pseudonym and has been taken down.
The federal complaint attributed "dirt nap" and "scum" statements to Mulqueen as well as several racist and obscene statements.
"The first wave to protect against is the inner city scum, do all you can to waste these lowlifes but be mindful of your ammo," Mulqueen was quoted as posting. "Use blades when you can to conserve bullets."
He also allegedly said he wanted all of President Barack Obama's followers dead, calling them "traitor scum."
"Death to them all," he said, according to a police report.
Police found two rifles, bulletproof body armor, bayonets, 100 rounds of ammunition -- including armor-piercing bullets -- and a sword at his home. But Mulqueen indicated in court Tuesday that he didn't intend to follow through on his threats, telling the judge, "I never meant any harm to anybody."
"I posted threats that I shouldn't have made," he admitted. He said he was angry because the politicians were proposing "legislation I found to be unconstitutional." He did not elaborate.
Police said the weapons were illegal because Mulqueen had drunken-driving convictions.
The federal indictment did not name Mulqueen's targets, but police listed the politicians' names when Mulqueen was arrested last month.
It was disclosed in court Tuesday that a "political activist" who was not an officeholder was also on Mulqueen's list. Neither defense attorney Jason Ser nor prosecutor Ilan Graff would identify that person.
Judge Kenneth Karas said that in the plea agreement, the defense and prosecution agreed that federal guidelines call for a sentence of 12 to 18 months. The judge warned Mulqueen, however, that he could sentence him to as much as 15 years, the maximum he would have faced if convicted at trial.
Sentencing was set for Oct. 16. Mulqueen is being held without bail.
Mulqueen still faces a charge in state court concerning the illegal weapons. His lawyer said Tuesday that a deal may be in the works there as well. Mulqueen was also charged a month ago with food stamp fraud. He pleaded not guilty.