That Old-Time Religion in Modern America by D.G. Hart Ivan R. Dee, 246 pages, $24.95 TO LISTEN to the more lurid claims of the ACLU, you’d think that evangelical Protestants were dominating American culture as never before. But this is not quite so. Yes, evangelicalism is still a presence in American life, and an important one, but it reached the height of its influence roughly a century ago. In “That Old-Time Religion,” D.G. Hart explores the change in the fortunes of evangelicals, taking up in particular their engagement with an increasingly secular society.