I’ve been tracking all of the major newspaper endorsements here at The Nation (following my practice since 2000) and most papers will have made their picks by Sunday, although some wait until the final weekend. Until now, the endorsements have been split, with Obama getting the edge in the number of larger papers, and Romney earning some key switches from papers that backed Obama in 2008.
This chart for the top 100 papers  finds Obama with 23 endorsees to Romney’s 19, and a nice edge in circulation numbers—and with expected backing from the NYT not included yet, which will certainly boost his margin. [UPDATE: The Times, indeed, endorsed Obama "enthusiastically" tonight. But the Des Moines Register in swing state Iowa went for Romney, the first time it has backed a GOPer since...Nixon] Go here for updates on this and other campaign news all weekend.
The San Jose Mercury-News today endorsed  Obama, as it had in 2008. This is not reflected in chart mentioned above. Ditto for the Minneapolis Star-Tribune. The Miami Herald, in a key move, also has endorsed  Obama: “In the end, Mr. Obama’s policies across the board — the environment, social policy, taxes and immigration — offer a more generous vision for America. The issues he has fought for, coupled with the lingering doubts about Mr. Romney’s persona and his true intentions, make this a clear choice.”
The Daily News  in Los Angeles has backed Romney but the San Francisco Chronicle went for Obama as expected. Of course, California, in our undemocratic Electoral College system, is not in play at all.
The Chicago Tribune--often conservative--endorsed native son Barack Obama for president. The paper, once rigidly conservative, is again owned by Republicans but still backs the president. As it admits, “On questions of economics and limited government, the Chicago Tribune has forged principles that put us closer to the challenger in this race, Republican Mitt Romney. We write with those principles clearly in our minds. Romney advocates less spending, less borrowing — overall, a less costly and less intrusive role for government in the lives of the governed.” But his deficit plan is not good, and Obama’s foreign policy views much better.
UPDATE SUNDAY Bunch of new endorsements Sunday morning. According to this non-partisan chart , the circulation of the papers among the nation's 100 largest that are backing Obama is now 8.6 million, vs. 4.3 million for Romney, with 32 nods for the president and 24 for the challenger (of course, many are in states that are not being hotly contested).
Among the latest: In key swing state Ohio, the Cincinnati Enquirer, usually Republican, backed Romney--but also Sen. Sherrod Brown. However, the Toledo Blade went for Obama. In another battleground, the Richmond Times-Dispatch endorsed Romney.
The Detroit Free Press picked Obama (balancing the Romney-backing of the Detroit News). The Pittsburgh Post-Gazette and the Buffalo News both chose Obama, as did the Hartford Courant and the News & Observer in Raleigh, N.C. and the paper in Lexington, Ky. The Oklahoman in Oklahoma City went for Romney.
For campaign updates all weekend, go here.