Intrade,,,,hasn’t been useful in a long time....It can and is being gamed
It depends on what you mean by "useful".
Some people think that wealthy leftist investors deliberately "game" Intrade by executing trades that they know undervalue the likelihood of wins by more conservative candidates, and that therefore the Intrade odds are not useful as predictors of election outcomes.
It seems to me that any conservative who genuinely believes this to be the case, and who wants to pocket some easy money, can just go on Intrade and take the other side of those leftist investors' politically-motivated trades.