As the old saying goes, you never get a second chance to make a first impression. That isn't to say that first impressions are necessarily immutable destiny in politics, since there are those who have bombed in their national debut and turned things around, and others who looked terrific at first but turned out to be something less. Bill Clinton gave a famously terrible speech at the 1988 Democratic convention, and Sarah Palin was dynamite in her speech at the GOP's 2008 gathering. Nevertheless, there are some things you just can't overcome, particularly if what caused them wasn't a bad night's sleep but the very core of your being.
A year or two ago, if you asked Republicans to list their next generation of star's Ted Cruz's name would inevitably have come up. Young (he's only 42), Latino (his father emigrated from Cuba), smart (Princeton, Harvard Law) and articulate (he was a champion debater), he looked like someone with an unlimited future. But then he got to Washington and started acting like the reincarnation of Joe McCarthy, and now, barely a month into his Senate career, we can say with a fair degree of certainty that Ted Cruz is not going to be the national superstar many predicted he'd be. If things go well, he might be the next Jim DeMint—the hard-line leader of the extremist Republicans in the Senate, someone who helps the Tea Party and aids some right-wing candidates win primaries over more mainstream Republicans. But I'm guessing that like DeMint, he won't ever write a single piece of meaningful legislation and he'll give the Republican party nothing but headaches as it struggles to look less like a party of haters and nutballs.