What is the meaning of 'moral reckoning'?

Solution 1:

A "moral reckoning" is the evaluation of and subsequent holding responsible for one's morality and/or for the morality of one's actions, most especially one's immoral actions. A moral reckoning can be self-imposed or be imposed by another or others.

The word "shame" in the question "Have you no shame?" is what is suggestive of Biden framing voting writes as a moral reckoning, shame being one's pat emotional response to a moral reckoning when it's found that one or one's actions are or have been immoral.

Basically, it's being posed that Biden's question suggests that the immorality of supporting and passing voter suppression laws is making those who are doing so lose face, so he's asking the rhetorical question "Have you no shame?" as he wonders aloud why they brazenly don't care they're losing face by knowingly continuing to very publicly engage in that immorality unabashedly and unrepentantly.

Please note that this answer does not express any personal opinion I hold but is merely answering the question at hand regarding the English language and usage in quoted material that expresses political opinions within, both in a direct quote from a politician and in an accompanying narrative about that quote written by an unknown party.