Democrats Eying Future Presidential Campaigns from Prison?

With news that a few prominent Democrats are agitating to allow prisoners the right to vote in federal elections questions arise as to why and how such a program of thought developed. 

https://www.yahoo.com/news/aoc-joins-bernie-in-backing-voting-rights-for-prisoners-163930237.html

Traditionally those that have lost the right to freedom have lost the right to vote too. Those that disrespect the laws lose certain protections of the law; and civic rights, until all of their rights are restored upon completing sentence and parole.

Millions of convicted felons in prison have tight political organization-gangs that might like to join the Democratic party to elect some of their own to office in order to gain better living conditions, to elect better judges and politicians that understand the trying challenges prisoners have toward escaping to better, upwardly mobile lives.

With Democrats possibly becoming concerned about being charged and convicted of crimes while in office, the practical expediency of making it possible for convicted felons to vote and run for office while in prison may have seemed a conservative step for them to take.