Mobs attacked homes of leaders of the two houses of Congress on the eve of a new session and the swearing-in of lawmakers.
Police said fake blood and a pig’s head were left outside the California home of Nancy Pelosi, the Democratic Speaker of the House of Representatives.
In Kentucky, graffiti was scrawled on the house of Senate Majority Leader Mitch McConnell, a Republican.
Mr McConnell’s house in Louisville was daubed with the words “were’s my money” and “Mitch kills the poor”.
In a statement, Mr McConnell said he appreciated all Kentuckians who took part in the democratic process “whether they agree with me or not”.
“This is different,” he said. “Vandalism and the politics of fear have no place in our society.”
While San Francisco police said they were investigating the incident at Ms Pelosi’s home. Graffiti was daubed on her garage door, which was later covered over with black plastic bags.
Congress is deadlocked over a relief package for the coronavirus pandemic.
On Tuesday, the House voted to increase the one-off payments sent to individuals from $600 to $2,000. The Democratic-controlled chamber passed the bill with the help of more than 40 Republicans.
But the Republican-led Senate has not approved the bigger cheques, despite calls to do so from US President Donald Trump.