As a rule, all policy proposals should be evaluated on the merits. It’s not enough to simply say, “It must be a good idea if so-and-so thinks it’s a bad idea” – such a tack is intellectually lazy, unserious, and best avoided.

There are exceptions to the rule.

Former President George W. Bush said the United States must show that it can follow through on its promises, and argued against the lifting of sanctions against Iran during rare remarks about foreign policy in a meeting with hundreds of Jewish donors [in Las Vegas] Saturday night. Mr. Bush told the 700 donors attending a closed-door Republican Jewish Coalition spring meeting that he would not criticize President Obama, whose aim to degrade and ultimately destroy the Islamic State he applauded. But the former president nevertheless offered comments that many in the audience viewed as a tacit critique of his successor.

As best as I can tell, there is no video or transcript available of the former president’s remarks, so we’re relying on attendees’ accounts of what Bush said. Word-for-word quotes should probably be taken with a grain of salt.

With that caveat in mind, the Republican reportedly said the international framework on Iran’s nuclear policy would be a bad long-term proposition: “You think the Middle East is chaotic now? Imagine what it looks like for our grandchildren. That’s how Americans should view the deal.”

Left unsaid: if there’s one person who knows all about Middle East chaos, it’s George W. Bush.

The former president also reportedly told his audience, “Pulling out of Iraq was a strategic blunder.”

Look, there’s probably little point in rehashing the scope and scale of George W. Bush’s catastrophic failures. The record is unambiguous; his misjudgments are the stuff of legend.

But so long as the former president is dipping his toes back into the public debate, let’s keep a few pertinent details in mind:

1. Presidents who launch two massive wars that destabilized the entire Middle East probably shouldn’t warn about his successor making the region “chaotic.”

2. When U.S. forces withdrew from Iraq, it was under the terms of a Status of Forces Agreement negotiated by George W. Bush.

3. Bush may not like the idea of a nuclear agreement with Iran, but President Obama is now making up for the fact that Bush could have struck a better deal but failed to even try, and Iran’s nuclear capabilities grew far more serious – without consequence – on Bush’s watch

All things considered, maybe Bush should head back to the painting studio for a while longer, hoping Americans will have more time to forget the enormity of the mess he left for his successor to clean up.

As for the broader political dynamic, part of me wonders whether Bush has inadvertently done Obama a favor – as Congress considers U.S. policy towards Iran in more detail, Americans agree with the White House , while George W. Bush and Dick Cheney disagree. I can think of worse messages for the president to push as the debate continues.

All of this, of course, comes against the backdrop of the 2016 presidential campaign, where Bush’s brother is considered a leading candidate. The former president recently acknowledged the fact that he’s a “problem” for Jeb Bush, but that apparently won’t stop George W. Bush from occasionally making things worse.

Postscript: Josh Rogin’s report on Saturday’s event added, “For George W. Bush, the remarks in Vegas … revealed that he takes little responsibility for the policies that he put in place that contributed to the current state of affairs.”