Former President George Bush spoke to a packed house yesterday in Atlantic, a rally organized by his son’s presidential campaign. The elder Bush offered an assessment of his son’s character, not on his son’s stance on issues. In December, critics charged Bush’s son, George W., was a lightweight and not up to debating his challengers. That dig has died down a bit, but dad Bush sought to squelch it yesterday. The former president said his son was strong enough to take the heat and it comes with the territory. Bush told the students in the audience that they “ought to be damn glad I’m here” because they got out of class to hear his speech. The Ex-President made a surprise stop at his son’s Iowa campaign headquarters yesterday afternoon. After some handshakes and pictures with Bush campaign staffers, the former President sat down to work the phones. One call was answered by a 15-year-old eastern Iowa girl who thought she was party to a practical joke when Bush told her who he was. She hung up on him.The elder Bush won Iowa’s Caucuses in 1980 — a win which catapulted him into the Vice Presidency. Then, in 1988 — Bush finished third in Iowa, behind Bob Dole and Pat Robertson, but went on to win the Presidency that year. As for his son’s chances in Iowa, Bush says a lot of credit comes from Bush supporters and staff.The ex-President delivered speeches in Atlantic and Des Moines yesterday.