Special counsel Robert Mueller, who has been probing Russia's meddling in the 2016 election and possible coordination with the Trump campaign, has spent more than $3.2 million in four-and-a-half months, according to a report released Tuesday. Meanwhile, the Department of Justice spent $3.5 million to support the investigation.

Why it matters: Some GOP members have criticized the spending, and President Trump lashed out on twitter in May, saying "The Russia-Trump collusion story is a total hoax, when will this taxpayer funded charade end?" But partisan outcries about the use of taxpayer funds for government investigations are nothing new.