Thank you.
"Wasn't Brooke defeated in the 1978 GOP primary by a conservative, who in turn lost to Tsongas in the general?"
No, he didn't lose in the primary. You're confusing that with New Jersey where the very liberal Clifford Case was defeated by Conservative Jeffrey Bell, and lost in turn to the newcomer Bill Bradley. Interestingly enough, most liberals were backing Brooke in MA because they felt it important to keep an African-American in the Senate (Brooke's voting record, of course, was almost indistinguishable from his colleague Ted Kennedy's). Then-Lowell Congressman Tsongas was regarded as slightly more Conservative than Brooke. 1978 was actually a year when there was a reaction against the left in MA, tossing out both Gov. Mike Dukakis in the Dem. primary in favor of bonafide Conservative Ed King, and then Tsongas over Brooke (not helping Brooke was his very messy divorce, which contributed to his defeat). I always wondered if Brooke had won a 3rd term, how he would've functioned in a GOP-majority Senate.
Welcome back. Your divine political wisdom is in dire need here.