It might be easy to forget, now that he has endorsed and defended Donald J. Trump to the ridicule and anger of fellow Republicans he called friends, that Gov. Chris Christie of New Jersey was himself once a leading, if not the leading, presidential hopeful in his party.

Then came revelations of a scheme so preposterous that it was hard to believe: Aides to the governor had deliberately created a traffic jam at the world’s busiest bridge as political payback.

The trial in the George Washington Bridge lane-closing scandal, which is scheduled to open on Thursday with jury selection, will play out like a documentary on the rise and fall of Mr. Christie’s presidential ambitions, a tell-all tale of how he and his aides built his administration and his 2013 re-election campaign with an eye to winning the White House, then scrambled to contain the damage as inquiries into the lane closings began to wreck those hopes.