It was one of the more striking responses from the news media to Wednesday’s killings at Marjory Stoneman Douglas High School in Parkland, Fla., an attack that quickly revived the national debate over restricting access to guns, and why politicians have taken few steps to do so.

The shift by The Post, among the friendlier news organizations toward Mr. Trump, was seen by proponents of gun control as a potentially favorable development.

In October, after a gunman killed dozens of people at a concert in Las Vegas, the paper editorialized that a 1990s-era assault weapon ban was merely “cosmetic,” and noted that mass shootings accounted “for a fraction” of domestic firearm-related deaths.

In Friday’s paper, The Post devoted two full pages to an editorial that called for, among other gun-control measures, the reinstatement of the 1994 federal ban on various assault weapons, which expired in 2004. “Mr. President, this is your moment,” the paper wrote, urging Mr. Trump to “prove how much you truly want to curb the carnage.”

Another Murdoch-owned outlet, however, showed no sign of championing gun control measures.

FoxNews.com published a tough critique of other networks’ coverage of the shootings, noting that the major network newscasts cited a statistic from an anti-gun group, Everytown for Gun Safety, that 18 school shootings had occurred this year. As other outlets, including The Washington Post, have pointed out, that statistic included a suicide at a closed school and an incident when gunshots were fired in a high school parking lot but no one was injured.