Hart goes on to spin that Romney is now the “challenger” to Perry, relieving him of the burden of having to play “King of the Hill” for the next eight months. Um, no. First, a one-day flash poll from Rasmussen does not make Perry the front-runner. Second, Ronald Reagan carried the burden of front-runner in the ’80 campaign after Ford decided not to run; I doubt he considered it a hindrance. That’s the point of the whole “next in line” thing; John McCain’s riches-to-rags-to-riches campaign is the exception, not the rule.

Nevertheless, there is a case to be made that Perry’s entry into the GOP nomination process may help Romney. The basic dynamic of the race remains, under my analysis, Romney vs. Not Romney. Perry’s entry divides the Not Romney vote, which may be divided further still by other late entrants. As RCP’s Sean Trende pointed out this week, a protracted campaign like the Dems had in 2008 has advantages for Romney. The early primaries and caucuses must award delegates proportionately; later states are free to adopt a winner-take-all system, and some have. The early states also tilt more conservative and evangelical than the later states. Thus, if Perry (or Bachmann for that matter) is unable to unify the Not Romney vote — either because of their own failings or other late entrants — Romney’s odds of securing the nomination may increase in a war of attrition. That’s the more important “time” factor this cycle.