There's a bigger threat lurking for Sinn Fein
Gerry Adams's arrest may damage the party's election prospects, but it's their protest politics that will ultimately fail them at the ballot box.
Call me crazy, but it's possible that the questioning of Gerry Adams over the murder of Jean McConville may not be the major threat to the Sinn Fein surge. It may be something else entirely.
You will often find that big news about a company or the economy at large will not hit share prices when that news is finally confirmed. Because it is usually said that the market had priced that information in already.
In the case of Sinn Fein, a lot of the new Sinn Fein voters have priced in the information about Gerry Adams's past already. There is no doubt that it makes Mary Lou & Co squirm when they have to get weaselly about Gerry and his past and the past of the party grandees in general. And there's no doubt that reading afresh about Jean McConville being dragged screaming from her house in front of her kids reminds people where Sinn Fein comes from and possibly makes the things that were done back then more real for a generation who never lived through it. But will it turn them off to that extent? Possibly not.