The controversial decision regarding Jerusalem made by President Trump was:
2. Jerusalem was made the capital of Israel.
This decision was significant because it recognized Jerusalem as the capital of Israel, a move that was highly debated and stirred up tensions in the region. The status of Jerusalem is a sensitive and complex issue due to its significance to both Israelis and Palestinians. This decision by President Trump diverged from the long-standing international consensus that the status of Jerusalem should be determined through negotiations between Israelis and Palestinians. The decision led to various reactions from different countries and sparked protests and debates worldwide.