On March 19 , Obama became the first sitting president to appear on a late night talk show when he was a guest on '' The Tonight Show with Jay Leno '' . On April 2 , Obama attended the G-20 London Summit . On April 17 – 19 he attended the 5th Summit of the Americas where he met Venezuela 's President Hugo Chavez , a longtime enemy of Washington , who shook his hand and gave him the book '' Las venas abiertas de América Latina '' ( '' Open Veins of Latin America '' ) of Eduardo Galeano while media was present . On April 28 , day 99 of Obama 's presidency , Senator Arlen Specter ( a former Democrat who switched to the Republican party in 1966 ) returned to the Democratic Party . Specter increased the Democratic senators to 59 , one short of a filibuster-proof majority . At the conclusion of the first 100 days , over 100 federal judgeships remained vacant
5th Summit of the Americas
5th Summit of the Americas
First 100 days of Barack Obama's presidency