George Clooney has signed on for another special guest appearance as the Barack Obama re-election campaign takes its summer fundraising tour across the Atlantic in pursuit of Euro-cash. The Obama campaign posted an invitation on its website Friday revealing that the presidential pal-in-chief will appear at a pair of Americans Abroad for Obama events Aug. 27 in Geneva, Switzerland. Clooney, who usually spends summers at his villa on Italy’s Lake Como, made a similar appearance across the Swiss border on behalf of then-candidate Obama during the run-up to the 2008 general election. Charles Adams, co-president of the campaign’s European outreach...