Nick uses the bandwagon effect first when he is making one of his arguments. He is trying to express his opinion towards the inefficiency of the death penalty,but he doesn't form his own opinion. Gillespie just sides with his particular political group. "As a libertarian, I'm not surprised that the state is so incompetent that it can't even kill people efficiently." Gillespie only forms this opinion because it's what his"group" believes.
Gillespie uses the pessimism bias next, when he is discussing the uncanny costs of the death penalty. "I'm sure death costs more in California (everything else does) than in other states, but there's just never going to be a way to make it less than a huge waste of taxpayer money." Nick's opinion is an example of the pessimism effect because he is just assuming that since California is more expensive with other things, that the costs to pursue the death penalty will be more there too.
"So the death penalty wastes money," said Nick,"has no effect on murder rates, and is sometimes tossed at innocent people. Those three reasons are more than enough to end it once and for all." In this argument, Gillespie uses the framing effect. He is able to form three conclusions from the same information.
In Nick Gillespie's attempt to persuade his readers that the death penalty is a bad thing, many cognitive biases are used by him. It's debatable whether or not he's write, but it's not debatable that he uses bias opinions throughout his article. Does this make Nick's argument stronger or weaker? That's up to you.