Tancredo's bowing out isn't a defeat for the restrictionist cause he championed. His effort received no support from the Republican establishment or putatively mainstream conservative media outlets like the WSJ. Yet every remaining candidate in the Presidential race--Democrat and (especially) Republican--save the consistent Dennis Kucinich, has taken a more restrictionist tone in their public rhetoric than their voting records indicates they'd like to. He has nudged the entire campaign away from advocating open borders. And having him actively back in the House has its own benefits (hopefully he will reconsider his decision not to seek re-election next year, a reversal he has made in the past).
My support is now more firmly behind Ron Paul, who has been good on the illegal underclass immigration front and, excepting Duncan Hunter, has the best overall immigration voting record among the Republican contenders. And Paul's foreign policy toward the is head-and-shoulders above the rest of the GOP's Presidential field.
Tancredo is now supporting Romney, who I like most among the four (or five, if Thompson is included) top-tier candidates. His obsession with number crunching and data perusal are welcome changes from the ideological orientation the Bush administration has offered for the last seven years. It's probably safe to allot him some rightward premium on account of having been the governor of the nation's most leftist state. To the extent that he shifts politically from where he had been in Massachusetts, it will almost certainly be to the right.