What was the primary goal of the strategic defense initiative

Strategic Defense Initiative was a program created during the presidency of Ronald Reagan, aimed at creating a space missile shield in which ballistic missiles from the Soviet Union could be destroyed outside the atmosphere. Due to its futuristic nature, the project was nicknamed Star Wars, like the film saga.

It turned out later that the SDI project was impossible to implement due to the huge costs, but the United States continued to develop the project to force the Soviet Union to respond. The Soviet Union would then invest its last billions in an impossible project. In the Soviet Union a project was indeed started to improve its existing A-135 System space shield around Moscow, but this project eventually came to a halt (although there were tests again in the 90s and 2004).  

The project continued under the name National Missile Defense in the United States and is part of the U.S. Missile Defense System, which must stop rocket weapons from Iran and North Korea against European countries and the United States itself.

it affected it because the kingdoms (with trade) slowly got richer and richer.