HILTON HEAD ISLAND, S.C. -- Rick Santorum is running for president but his campaign speeches sometimes sound like he's working toward tenure.

The Republican quotes Irish statesmen and French historians, traces word origins and explains Islam to the Christian conservatives who have great sway in South Carolina's Saturday GOP primary. He recommends books, cites academic studies and doesn't shy from footnoting his own unscripted remarks.

At times, Santorum's events more closely resemble a somber college lecture than a raucous political rally -- informative, if not always inspirational....

Often, Santorum commends one of his recent reads, David Hackett Fischer's "Washington Crossing," to his audiences. He mentions Edmund Burke, the 18th Century historian. He quotes Alexis de Tocqueville's study of American democracy....