Mr. Gingrich represents a new kind of Catholic, one very different from the Kennedys, who were Democrats, political liberals and cradle Catholics shaped by the Irish immigrant church. To a Kennedy-era Catholic, divorce was a sin, labor unions were a virtue and anti-Catholic bigotry was a staple in many Protestant circles.

Mr. Gingrich is a culture wars Catholic for whom the church seems a logical home for conservative Republicans. Generations removed from the Kennedy years when Catholics predictably voted Democratic, this is a new era in which conservative Catholics and evangelical Protestants have joined forces in what they see as a defining struggle against abortion, same-sex marriage and secularism…

Like many recent converts to the church, Mr. Gingrich is what Catholics call a “John Paul II Catholic,” those inspired by that pope to embrace traditional church teaching, eschewing calls to liberalize or modernize the faith, Mr. Novak said…

Mr. Gingrich has increasingly warned that the United States is threatened by the encroachment of both secularism and Islam, and those who know him say he sees the Catholic Church as a powerful and convincing bulwark against it. The theme of secularism as a threat to Europe is a frequent one for Pope Benedict, who spoke about it in his speech to the American bishops the day Mr. Gingrich was in the crowd at the basilica.