Wikipedia:
http://en.wikipedia.org/wiki/Ed_Brooke
Brooke...
often had conflicts with President Richard Nixon, particularly in 1970, when Brooke helped lead the movement to stop the Senate confirmation of the President's nominee to the Supreme Court, Harrold Carswell. Brooke was re-elected in 1972, defeating Democrat John J. Droney 62%-34%. However, he lost much of his popularity during his second term after a contentious and widely-publicized divorce. He lost a bid for a third term in the Senate elections of 1978 in the general election to Paul Tsongas. He remains, as of 2008, the last Republican senator from Massachusetts.
Maybe now we know who sparked it.