Illinois may actually serve as a microcosm for the rest of the primary contests [well before last night]. The demographics in Illinois are not dramatically different. Romney wins with moderate, pragmatic, Republicans, while Santorum does well with more ideologically driven Republicans.
However, in Illinois, the numbers have shifted in Romney’s favor. Illinois Republicans are quite practical in nature and less swayed by Santorum’s ideological rhetoric as explained by former Governor Jim Edgar.
Illinois may serve as an indicator of future primary results, If true, the signs are ominous for Rick Santorum.
Santorum will continue to do well in more ideologically driven states, while Romney will pick up states packed with moderate Republicans. This divide will send Romney to the Republican nomination eventually, and reduce Santorum to a blocker role.
Santorum just couldn’t win enough moderate voters at the end of the day.