(CNN) President Donald Trump's interpretation of Russia's 2014 annexation of Crimea is, to say the least, charitable to Russian President Vladimir Putin in that Trump blames former President Barack Obama for Putin's aggressive action.

"He allowed Russia to take Crimea," Trump said Friday of his predecessor, on whose shoulders he places blame for many things. It was the second time in a week he has blamed Obama for Putin annexing Crimea.

"I may have had a much different attitude," Trump said.

Except within a few breaths of suggesting Obama's weakness had allowed Putin to take Crimea, Trump was talking about wanting to be nicer to Russia and Putin and reconstitute the G8 with Russia as a member.

Trump seems to be saying Putin would never have dared annex Crimea under his watch, but now that he's there, no big whoop.

The world's largest industrialized democracies, including the US, kicked Russia out of their club in 2014, turning what had been the G8 into the G7.

But all of that, in Trump's mind, is Obama's fault.

Trump laid it out when he talked to reporters during an ad hoc news conference Friday outside the White House about whether he'd convene a summit with Putin. Read this exchange and try to follow his logic:

TRUMP: It's possible that we'll meet, yeah. And I thought -- you know, this all started because somebody -- one of you -- asked, "Should Putin be in the G7?" I said, no, he should be in the G8. A few years ago, Putin was in what was called the G8. I think it's better to have Russia in than to have Russia out, because just like North Korea, just like somebody else, it's much better if we get along with them than if we don't.

So it's possible. Just so you understand --

REPORTER: Is Crimea part of Russia? Do you --

TRUMP: No, no. President Obama lost Crimea, just so you understand. This was long before I got there. Just -- I want to make it so the fake news prints it properly. President Obama lost Crimea.

REPORTER: So it's his fault?

TRUMP: Wait, wait. That's his fault. Yeah, yeah, it's his fault. Yeah, it's his fault.

REPORTER: How is it not Putin's fault, sir?

TRUMP: The President -- just so you understand --

REPORTER: How is it not Putin's fault, sir? How is it not Putin's fault? He invaded them.

TRUMP: Because -- because Putin didn't respect President Obama. President Obama lost Crimea because President Putin didn't respect President Obama, didn't respect our country and didn't respect Ukraine. But President Obama, not Trump -- when it's my fault, I'll tell you. But President Obama gave away that. Now, President Obama, by not going across the red line in the sand that he drew -- I went across it with the 59 missile hits. But President Obama, when he didn't go across the red line, what he gave away, nobody even knows. But just to put it -- one more time, President Obama gave away Crimea. That should have never happened.

What Trump is saying is that since Obama didn't appropriately enforce a red line he drew with Syria over the use of chemical weapons, that Putin was emboldened to go into Crimea and force a questionable referendum there.

Got that? Putin should be in the G8 because it's Obama's fault that he annexed Crimea because Putin didn't respect Obama. Putin, Trump seems to say, had no choice. He had to take on Crimea.

To punish him for it would be like punishing a dog for eating steak off the kitchen counter. It's not the dog's fault for eating the steak. Whoever left the steak there is to blame.

That Obama's failure to enforce his red line led to an emboldened Putin is not a new argument, actually. Julia Ioffe deconstructed it in The Atlantic a few years ago

Trump is saying that because he responded to Syria's use of chemical weapons with missile attacks, whereas Obama did not back up his red line with military action. And so Putin will now have more respect for the US.

JUST WATCHED A CNN report from 2014: Putin takes victory lap in Crimea Replay More Videos ... MUST WATCH A CNN report from 2014: Putin takes victory lap in Crimea 02:07

Obama has argued his decision not to strike Syria after consulting Congress took more political will than simply ordering a strike. That's a debatable assertion, to say the least. Clearly Trump would sneer at it.

The actions of neither man led to the ouster of Syrian President Bashar al-Assad.

Fox News' Steve Doocy also asked Trump on Friday if he'd sit down with Putin in a summit and the President's answer started in the same place, but ended on the 2016 election and Russian meddling instead of Crimea.

"We may. It started because a reporter shouted to me, should Putin be in the G8? I said he should be in the G8. It used to be the G8 a few years ago. President Obama didn't like him, even though they gave advanced notice about the election to Obama. People forget about that. Obama was told by CIA or somebody, FBI, about Russia. He didn't do anything about it. How come he never gets blamed? In September just before the election, my election."

Putin, Crimea and the G7 née G8 have been much on Trump's mind.

During the G7 meeting in Canada a week ago, according to a report in BuzzFeed, he downplayed down the effect of Russia's annexation, and joked about how people in Crimea speak Russian

He encouraged the world leaders there from France, Germany, Japan, Canada, Italy and the UK to readmit Russia. He talked about it all at a news conference, where he first made the "blame Obama" argument.

It's interesting to read the 2014 account by CNN's Jim Acosta about world powers kicking Russia out of the G8. At the time the G8 members excommunicated Russia, Putin had planned a G8 summit in Sochi to show off the city to world leaders just after the Olympics had been held there. The G7 countries snubbed Putin and met elsewhere.

The same morning Trump was blocking for Putin in terms of blame for annexing Crimea and advocating Russia in the G8, his own defense secretary, James Mattis, was striking the opposite tone during a graduation speech at the US Naval War College.

"For the first time since World War II, Russia has been the nation that has redrawn international borders by force in Georgia and Ukraine while pursuing veto authority over their neighbors' diplomatic, economic and security decisions," Mattis said. "Putin seeks to shatter NATO. He aims to diminish the appeal of the Western democratic model and attempts to undermine America's moral authority, his actions are designed not to challenge our arms at this point but to undercut and compromise our belief in our ideals."

Those are two very different messages out of the administration with regard to Russia in the space of one morning.