Conversation so far:
What led up to him losing his seat in the senate?
Gruening won the bitterly fought primary, with about 55 percent of the vote to Gravel's 44 percent.
Why did that happen?
As an insurgent candidate in 1968, Gravel had never established a firm party base.
What did he do instead?
Gravel was the last Democrat to represent Alaska in Congress for 28 years.
Are there any other interesting aspects about this article?
Several factors made Gravel vulnerable.
Like what?
The sources of Gravel's campaign funds, some of which came from political action committees outside the state, also became an issue in the contest.
Why were they an issue?
CANNOTANSWER.

Question: What else can be said about the loss of his senate seat?
Self-contained rewrite: What else can be said about the loss of the senate seat other than Mike Gravel being vulnerable?