I believe Obama was right that is/was the most important thing.

It says,
"Obama’s former chief of staff, Denis McDonough, told the Post. Russia’s hacks and leaks were bad, but corruption of voter rolls and election tallies would be far worse. So the Obama administration focused on alerting state officials, fortifying cyberdefenses, and privately threatening Russia with retaliation."

Obama thought that was the most important thing, but the article does NOT make any conclusion about whether or not he was successful.

I don't know HOW anyone would know. There are so many different schemes that COULD have been used, marrying to voter

have been worse, but there is no evidence of it. Could it happen, sure. Did it happen, hundreds looking have found no evidence of it. Apparently, Obama's warning to shore up security worked.

It says he thought that corruption of voter rolls would have been worse, that does not necessarily mean it didn't happen. He may not know whether it did or didn't happen.

words than necessary

Why didn’t Obama raise public alarms about Russian infiltration? Because that might have backfired. “Trump was predicting that the election would be rigged,” says the Post. “Obama officials feared providing fuel to such claims, playing into Russia’s efforts to discredit the outcome.” According to the paper, Obama and his team “worried that any action they took would be perceived as political interference in an already volatile campaign.” Rather than speak up when the CIA first warned him about Putin’s moves, Obama waited for “a high-confidence assessment from U.S. intelligence agencies on Russia’s role and intent.” He asked congressional Republicans to join him in cautioning citizens and state election officials. You can argue that this was politically naïve. But Obama wasn’t playing politics. He was trying to unite the country. . .

. . . Many Republicans saw Obama and Hillary Clinton as greater threats than Putin. Senate Majority Leader Mitch McConnell resisted Obama’s pleas to warn the public about Russian interference, “voicing skepticism that the underlying intelligence truly supported the White House’s claims.” . . .

. . . The Russia investigation was never about Russia. It was, and is, about America. It’s about whether you put your country before a partisan or personal agenda. It’s about understanding that America isn’t just a plot of land. It’s an idea. We elect our leaders, our leaders follow rules, and they represent all of us. Obama was determined to preserve that idea, even at the risk of relinquishing the White House to Trump. The successor who betrayed him—and us—is unworthy of his office.

but to fail to disclose after Comey came out with that phony Hillary email story? TOTAL FUCKING BULLSHIT.

the game changed when Comey talked about the Hillary email bullshit