As a presidential candidate, he was awkwardly disconnected, a wealthy Republican who struggled to earn the trust of the conservatives in his party.

Now, two decades later, that candidate, the elder George Bush, is serving as a kind of political object lesson for a kindred spirit, Mitt Romney.

As Mr. Bush tried to do, Mr. Romney is working to bridge two worlds inside the Republican Party: an establishment wing with which he feels comfortable and a rabble-rousing wing that has a big influence over policy and ideology.

Mr. Bush managed to reconcile and unite both of those sometimes opposing forces, but not until he sought the White House as a sitting vice president in 1988. And those same divisions and suspicions from conservatives helped scuttle his re-election campaign four years later.

Mr. Romney now faces some of the same challenges.

His wealth, business connections and family ties have provided him access to party veterans and helped him carve out a path to the nomination. But he has failed to inspire confidence or passion among conservatives in 2012 in much the way that Mr. Bush failed to excite the Republican base of the early 1990s...