The critics were united. Confusion and inconvenience, they said, would lead to an embarrassingly low voter turnout at the special U.S. Senate election Gov. Chris Christie had called for a Wednesday in mid-October, a mere 20 days before the regularly scheduled November voting. And they were right. Only 24 percent of the state’s registered voters took part. It was higher than the participation rate when your average New Jersey fire district chooses its commissioners, but it was the lowest figure ever for a general election. Some performance. Some payoff for the $12 million extra it cost the state to vote on two days instead of one. Why did the governor set it up that way? If you’re not a rabid Christie partisan, the answer should be easy. As a candidate for a second term on the Nov. 5 ballot, he preferred not to share it with popular Democratic Senate candidate Cory Booker and diminish his own chances for the landslide victory he’d like to be able to flaunt when the time comes for him to pursue the 2016 Republican presidential nomination.