Mitt Romney declared in last week’s presidential debate that he’d do away with the Public Broadcasting Service. Maybe it was because he’d been given an advance look at Frontline’s essential election primer, The Choice 2012.

PBS has been part of the fabric of our democracy since President Kennedy’s Federal Communications Commission chairman Newton Minnow called commercial TV a “vast wasteland.” And of course it’s been a thorn in the side of politicians of every stripe, but mostly conservative Republicans.

Consider The Choice, which views Romney as a shape- shifting businessman, “a turnaround specialist” who “crafted himself to meet the politics of the moment.”

Barack Obama is an astute, if pie-in-the-sky, politician, “whose promise to unite the country ran into the harsh reality of politics.”

The two-hour documentary could stand as the most concise, level-headed political biography we’re likely to get this election season.

Directed by Frontline producer Michael Kirk, Choice begins its dual narratives with notable failures: Romney’s disastrous 1994 debate for Senate with incumbent Ted Kennedy and Obama’s 2000 loss to congressional incumbent Bobby Rush.

Both defeats were formative. Rush publicly dismissed Obama as “an educated fool,” tapping into perceptions of aloofness and arrogance that would dog the future president. Kennedy schooled a flustered Romney on policy.

The program then delves into the early years of candidates, interviewing family, friends, colleagues and journalists.

The Choice finds fascinating nuggets in these well-worn histories. In his 1972 high school yearbook, Obama thanks a pal named Ray, the school’s pot dealer, while a young Romney rarely spoke of his great-grandfather’s five wives and 30 children.

Frontline, though, isn’t after the salacious. Choice uses the personal facts to build convincing profiles of political character.

“He had come to see himself as a White Knight,” says the narrator, describing Romney’s years at Bain Capital, when investor profits in struggling companies often came at the expense of workers’ jobs. “He could fix almost anything.”