Jeffrey Toobin's latest book portrays Supreme Court Justice Antonin Scalia as increasingly cranky and partisan — and infuriated with Chief Justice John Roberts over the court's recent decisions on healthcare and immigration.

Toobin, who writes for The New Yorker and also covers the court for CNN, credits Scalia for a sea change in how both sides of the political spectrum think about the law. But he says the justice's bombast has become off-putting to more even-tempered colleagues.

Toobin's latest book, "The Oath," chronicling the Roberts court and the Obama presidency, is being released today. Here are 5 key takeaways:

Scalia 'furious' over healthcare and immigration

The book confirms previous reports that Roberts changed his vote in the landmark case over President Obama's healthcare law after initially siding with the conservative justices. But Toobin reports — as others have implied — that what pushed Roberts away was the conservative justices' insistence on striking down the entire health law.

"Scalia's view of the justices as gladiators against the president unnerved Roberts," Toobin writes.

The book describes Scalia as "furious" and "enraged" at Roberts — contradicting Scalia's public statements brushing aside any tensions.

Toobin's book says Scalia has become fixated more on politics — and particularly on Obama — than on legal scholarship, saying frustration over the healthcare ruling helped fuel his acerbic statement dissenting from the court's decision on Arizona's immigration law.

"Scalia was indeed unhappy with the immigration decision, but the splenetic excess of his Arizona opinion owed far more to his failure (as yet unknown to the public) in the health care case," the book says.

White House didn't consider State of the Union fallout

Republicans criticized President Obama for disagreeing with the Citizens United ruling in his 2010 State of the Union address. But no one in the White House had even considered the risk of publicly disagreeing with the court.

"During the discussions in Emanuel's office, as well as the president's own prep sessions, the propriety of challenging the Supreme Court had never come up," Toobin writes. "The group was so focused on pushing Obama's agenda that the issue of the justices' presence seems not to have occurred to anyone. The administration's anger about Citizens United was such that (even though no one said this specifically) the Obama team simply regarded the Supreme Court majority as another group of Republicans, deserving no greater deference than GOP senators or congressmen."