"The American" Tops The Holiday Weekend Box Office Exit popcorn-pic season, hello movies for grown-ups: Focus Features' George Clooney starrer " The American " topped the domestic box office with an estimated $16.4 million during the summer-ending Labor Day weekend. The assassin-themed thriller rang up $19.5 million in its first six days, after unspooling midweek to get a jump on the four-day frame. Two other wide openers bore the same R rating as "American" but seemed more restricted in audience appeal. Fox's crime actioner " Machete " topped daily rankings with $3.9 million in its first day of release on Friday, but the Robert Rodriguez-shepherded splatterfest quickly ceded its lead to the more broadly appealing Clooney pic and fetched $14 million in second place through Monday. Warners' romantic comedy " Going the Distance " -- starring Drew Barrymore and Justin Long -- proved the weakest of the weekend debutantes,