How “Devil may care” is different from “After me the deluge”?

Question

I came across the phrase, “Devil may care” in the following sentence of Maureen Dowd’s column titled “The Son Also Sets” in September 22 New York Times.

“In 2000, when he (Stuart Stevens, Mitt Romney’s campaign strategist) worked for W., as New Hampshire Republicans headed to the polls on Primary Day to deliver a near-fatal 19-point drubbing of his candidate, Stevens headed out from his hotel carrying skis. Asked by a reporter about his insouciance, he replied that there was nothing he could do at that point.

But his “devil-may-care routine,” as The New Republic calls it, may be wearing thin. This isn’t merely a plotline for some future script.”

The idiom “devil-may-care” routine instantly reminded me of the cliché, “after me the deluge,” but I’m unable to fathom the difference of nuance between “devil may care” and “after me the deluge.”

I think both idioms concern the absence of the sense of responsibility. Are they close or very different in terms of the magnitude of irresponsibility, level of nonchalance and the nuance of destructiveness?

Can I use ‘devil-may-care” and “after-me-the-deluge” interchangeably to describe somebody's irresponsible attitudes /deeds, or not?

Answer 1

The phrase "devil-may-care" seems to refer to general carelessness, while "Apres moi le deluge" (originating with historical King of France Louis XV) seems to refer to a specific carelessness motivated by the fact that after the individual being careless is out of the position in which they have something to be careless about, the consequences have no effect on them. So, they can not exactly be used interchangeably, as someone who is being careless (someone who "is devil-may-care") might not be doing so because their thought process is that of "apres moi le deluge", but rather for some other reason.

Answer 2

To add to @Joe's answer (sorry not enough rep to leave a comment), they are not the same, because 'devil may care' implies the person simply does not care, while the quote from the King of France implies the person is beyond caring (they cared once but no longer), or they are powerless to take care, because circumstances have overtaken them, having your head cut off being an extreme case of incapacity.

Answer 3

To me, devil may care is so familiar as to have become effectively a word, while after me the deluge is a literary French phrase that I am not sure I have ever encountered in English before. It is certainly not an idiom in any kind of English I am familiar with.