After former President Donald J. Trump announced his vice-presidential pick, Senator J.D. Vance of Ohio, partisan media focused on two different versions of Mr. Vance — both of which have defined his time on the national stage.

Many conservative commentators and outlets applauded the former president’s choice, focusing on Mr. Vance’s conservative credentials as a senator and his loyalty to Mr. Trump, both in his policy positions and his efforts to downplay Mr. Trump’s role in the Jan. 6 attack on the U.S. Capitol. Some conservative publications, however, saw the choice as a boon to Democrats.

Most liberal sites characterized Mr. Vance as an opportunist by focusing on his past status as a prominent critic of Mr. Trump, highlighting Mr. Vance’s denunciations of Mr. Trump during his first presidential campaign. They also showcased the senator’s turn toward Mr. Trump, including his hard-line positions on abortion and the Jan. 6 attack, to paint him as a political extremist.

Here’s how a few outlets covered the news:

FROM THE RIGHT

Breitbart

Mr. Vance rose to prominence in 2016 with the publication of “Hillbilly Elegy,” a memoir about his childhood in Appalachia that doubled as a sociocultural analysis of problems in rural America, including poverty and the opioid crisis. He frequently denounced Mr. Trump that year, calling him “cultural heroin,” an “idiot” and a “total fraud.”

But since his election to the Senate in 2022, Mr. Vance has positioned himself as a conservative populist, closely aligned with Mr. Trump.