Political Memes

Acceptance of collateral damage is a well-established principle in international law.

If there's a military purpose proportional to the damage inflicted. Bombing a wedding because a few attendants are enemy combatants is not that.

it would be extremely difficult to make any serious argument that the drone strikes were exceptionally careless about collateral damage relative to the military gain by current standards and thus constitute a war crime.

That would simply mean only some were war crimes compared to a majority that were legal. Even if you're hitting one wedding for every nine enemy training camps, that one wedding is still a war crime. Also, I'd like to point out that the CIA is literally on record claiming international law is inapplicable to their drone strikes (back when they were still done by the CIA). Those are not the words of people not committing war crimes.

The CIA's general counsel, Stephen Preston, in a speech entitled "CIA and the Rule of Law" at Harvard Law School on 10 April 2012, claimed the agency was not bound by the laws of war

Selling weapons is not a war crime.

Which is not the only thing America was doing under Obama.

This support involves aerial refueling, which allows coalition aircraft to spend more time over Yemen, and allowing some coalition members to home base aircraft instead of transferring them to Saudi Arabia

In October 2016, Reuters obtained documents under the Freedom of Information Act showing officials had warned that the United States could be implicated in war crimes for its support of Saudi Arabia's intervention.

According to a March 2016 Human Rights Watch assessment, the U.S. involvement in certain military actions, including as target selection and aerial refueling during Saudi air raids "may make US forces jointly responsible for laws-of-war violations by coalition forces".

-https://en.wikipedia.org/wiki/United_States_support_for_Saudi_Arabian%E2%80%93led_operations_in_Yemen

Sounds real war crime-y to me.

You mean... trying to close it, restoring the standards to that of an ordinary prison instead of a torture camp, and releasing the vast majority of the prisoners when Congress refused to let him close it?

Obama did a lot to improve the conditions at Guantanamo bay, but still:

The report stated the United States violated international law, particularly the International Covenant on Civil and Political Rights, that the Bush Administration could not try such prisoners as enemy combatants in a military tribunal and could not deny them access to the evidence used against them.

-https://en.wikipedia.org/wiki/Guantanamo_Bay_detention_camp#International_law

This is one thing Obama didn't change to my knowledge. See also:

In March 2009, the administration announced that it would no longer refer to prisoners at Guantanamo Bay as enemy combatants, but it also asserted that the president had the authority to detain terrorism suspects there without criminal charges.

-https://en.wikipedia.org/wiki/Presidency_of_Barack_Obama#Guantanamo_Bay_detention_camp

This one is on the light end to be fair, but still a war crime.

If you think the president, and for that matter one of the least pro-Israel presidents since I've been alive could have easily "just done more" to prevent Israeli war crimes, you're out of your gourd.

I mean, Reagan did it, literally with a phone call. US presidents can "just do more" to prevent Israeli war crimes that they fund, arm and protect. Also least pro-Israel in what way? The only instance of him going against Israel that I know of is JCPOA, which does nothing to absolve him of Israel's war crimes in Palestine.