CT resident here—the real threat of voter fraud in this state is that there are many (six figures?) registered voters who are dead or no longer live at the current address.
I received a dead person’s letter authorizing the dead person to request a ballot, so I “know” the lists have not been purged of ineligible voters.
What would have to happen to cheat would be a corrupt election official in the town to accept the ballot from the dead person.
In CT we have plenty of corrupt officials—dime a dozen, especially in the big (D) cities.
Having dead on voter rolls is clearly problematic, and I can say so from an operational perspective.
In campaigns with limited funds (always the case for R’s in MA), you hate to pay for postage to send stuff to the dead. So, when you get partisan voting data (ie, what ballot someone took at a primary), you also request the latest voter registry, so that you can weed out some of the dead from mailings.
In MA, all this data comes from state-based databases. Removing the dead is a quantum process (updates at primary and general election times), and lags actual death by a significant delay. Hard to quantify, but enough of a delay for nefarious ‘rats to watch the obits, and match them up with voter registration lists.