Basically, it comes down to the fact that while Ellsberg might have been at risk by illegal activities of the Nixon administration, he was not at risk by the law itself, while Edward Snowden would be tortured as a matter of law and Department of Justice policy:

Many people compare Edward Snowden to me unfavorably for leaving the country and seeking asylum, rather than facing trial as I did. I don’t agree. The country I stayed in was a different America, a long time ago.

After the New York Times had been enjoined from publishing the Pentagon Papers — on June 15, 1971, the first prior restraint on a newspaper in U.S. history — and I had given another copy to The Post (which would also be enjoined), I went underground with my wife, Patricia, for 13 days. My purpose (quite like Snowden’s in flying to Hong Kong) was to elude surveillance while I was arranging — with the crucial help of a number of others, still unknown to the FBI — to distribute the Pentagon Papers sequentially to 17 other newspapers, in the face of two more injunctions. The last three days of that period was in defiance of an arrest order: I was, like Snowden now, a “fugitive from justice.”

Yet when I surrendered to arrest in Boston, having given out my last copies of the papers the night before, I was released on personal recognizance bond the same day. Later, when my charges were increased from the original three counts to 12, carrying a possible 115-year sentence, my bond was increased to $50,000. But for the whole two years I was under indictment, I was free to speak to the media and at rallies and public lectures. I was, after all, part of a movement against an ongoing war. Helping to end that war was my preeminent concern. I couldn’t have done that abroad, and leaving the country never entered my mind.

There is no chance that experience could be reproduced today, let alone that a trial could be terminated by the revelation of White House actions against a defendant that were clearly criminal in Richard Nixon’s era — and figured in his resignation in the face of impeachment — but are today all regarded as legal (including an attempt to “incapacitate me totally”).

(FYI, “incapacitate me totally” means assassination by Nixon’s people)

I hope Snowden’s revelations will spark a movement to rescue our democracy, but he could not be part of that movement had he stayed here. There is zero chance that he would be allowed out on bail if he returned now and close to no chance that, had he not left the country, he would have been granted bail. Instead, he would be in a prison cell like Bradley Manning, incommunicado.

He would almost certainly be confined in total isolation, even longer than the more than eight months Manning suffered during his three years of imprisonment before his trial began recently. The United Nations Special Rapporteur for Torture described Manning’s conditions as “cruel, inhuman and degrading.” (That realistic prospect, by itself, is grounds for most countries granting Snowden asylum, if they could withstand bullying and bribery from the United States.)

What he is saying here is that Snowden will be tortured if he ever enters US custody.

Hell, they did that almost 20 years ago in the case of Wen Ho Lee, where he spent months in pretrial solitary, largely because the prosecutors, and the counter-espionage apparatus, wanted to break him.

BTW, when we look at the NSA surveillance regime, it is what a former East German Stasi officer would call a totalitarian state’s wet dream:

Wolfgang Schmidt was seated in Berlin’s 1,200-foot-high TV tower, one of the few remaining landmarks left from the former East Germany. Peering out over the city that lived in fear when the communist party ruled it, he pondered the magnitude of domestic spying in the United States under the Obama administration. A smile spread across his face.

“You know, for us, this would have been a dream come true,” he said, recalling the days when he was a lieutenant colonel in the defunct communist country’s secret police, the Stasi.

In those days, his department was limited to tapping 40 phones at a time, he recalled. Decide to spy on a new victim and an old one had to be dropped, because of a lack of equipment. He finds breathtaking the idea that the U.S. government receives daily reports on the cellphone usage of millions of Americans and can monitor the Internet traffic of millions more.

You know, if your surveillance regime is something that gives a former Stasi agent a stiffie, you are doing something profoundly evil.