saudi arabia and the united states are strategic allies, and since president barack obama took office in 2009, the us has sold $110 billion in arms to saudi arabia. however, the relationship between saudi arabia and the united states became strained and have witnessed major decline during the last years of the obama administration, although obama had authorized us forces to provide logistical and intelligence support to the saudis in their military intervention in yemen, establishing a joint coordination planning cell with the saudi military that is helping manage the war, and cia used saudi bases for drone assassinations in yemen. in the first decade of the 21st century the saudi arabia paid approximately $100 million to american firms to lobby the u.s. government. on may 20, 2017, president donald trump and king salman signed a series of letters of intent for saudi arabia to purchase arms from the united states totaling us$110 billion immediately, and $350 billion over 10 years.