Saudi Arabia and the United States have a relationship that stretches back almost a century, since the 1933 kickoff of oil exploration in the kingdom.
Since then, the two countries have maintained a baseline of economic and security cooperation that has kept ties between them strong. Saudi Arabia is the US' largest foreign military sales customer, and the US has long had a physical and advisory military role in the kingdom.
While today there seems to be a strategic alignment between Saudi Arabia's interests in the region and those of the US, mostly centring around controlling Iran's regional reach, there have been low points in this relationship that were brought about by major events. Saudi Arabia has always sought balance between its role as a leader in the Arab world and its strong ties to the US.