Dingy nods in approval.

WASHINGTON — Sen. Charles Schumer said Thursday that some of the ads bankrolled by conservative mega-donor David Koch are “un-American.”

“I think the commercials he is running are against the American dream are un-American,” Mr. Schumer, New York Democrat, said on MSNBC’s “Morning Joe.” “I think what Harry Reid was saying is the actions are un-American, and they are, and they should change.”

David and Charles Koch have become favorite targets of Democrats in the run-up to the 2014 election, where they are trying to defend the Senate.

Republicans need to pick up a net of six seats to capture the upper chamber.

On Thursday, Mr. Schumer refused to say whether he agreed with Senate Majority Leader Harry Reid, Nevada Democrat, who called the Koch brothers “un-American.”