Barbara Bush was no stranger to Iowa, as befits a state with an outsized role in the presidential sweepstakes. She campaigned here with her husband and for her son, both of them destined to be president. She also visited Cedar Rapids and Dubuque in the late 1970s, campaigning for Republicans, and then in the 1980s when her husband was Ronald Reagan’s vice president.But perhaps her most charming visit came on April 21, 1992, when, as first lady, she took part in the opening ceremonies for the new PMX plant in Cedar Rapids.