Large, noisy demonstrations have flared across Anbar Province in recent days to protest what is widely perceived to be Prime Minister Nouri al-Maliki’s witch-hunt against Iraq’s Finance Minister Rafe al-Issawi, a leading Sunni politician. Maliki’s security force raided Issawi’s compound and arrested 10 of his bodyguards–following the same M.O. that led last year to Sunni Vice President Tariq al-Hashemi being convicted of murder in absentia after his bodyguards were allegedly tortured. (Hashemi has fled to Turkey.)

Maliki insists the security forces are simply following the law and investigating credible allegations that Issawi, like Hashemi, has been involved in terrorism. As it happens, a friend has provided me with a letter that General Ray Odierno, then the top U.S. commander in Iraq, wrote to Maliki in 2010. The letter (which is in Arabic) says that U.S. intelligence agencies have thoroughly investigated the charges against Issawi and found them to be uncorroborated. In the murky world of Iraqi politics, where courts are corrupt and government agencies often sectarian, this is about as convincing an exoneration as Issawi could get–coming as it did at a time when the U.S. still had a substantial military and intelligence infrastructure in Iraq, something that is no longer the case.

The letter exposes what is already obvious–that this is not a legitimate criminal inquiry but a partisan vendetta that is being pursued by the Shiite prime minister against his Sunni opponents. Given the way that Issawi has been able to turn out large crowds on his behalf, it is obvious that Maliki is playing with fire. If he keeps on this path, Sunnis are likely to protest not just with demonstrations but with bombs and bullets.