Donald J. Trump’s series of victories on Super Tuesday complicated the “Never Trump” movement that has been percolating in corners of the Republican Party, leaving the Manhattan businessman’s remaining rivals struggling for new ways to halt his march to the presidential nomination. After months of carefully plotting their primary state strategies, campaigns were left crunching numbers on Wednesday morning and dusting off history lessons about contested conventions and arcane ballot rules. On the face of it, campaigning proceeded as usual on Wednesday, with Senators Ted Cruz and Marco Rubio set to touch down in Kansas and Michigan for rallies; Kansas...