Newly elected members of Congress are like extras on a long-running television show: Each comes onto the set hoping to stand out only to end up in the back of a crowd scene while dreary, pampered has-beens soak up the air time. As usual, this year’s triumphant freshmen class—a whopping 87 of them members of the new Republican majority—expected it to be different. They wanted to be conquering heroes, vowing to get serious about America’s debt and choke off the federal spen...