Iowa Democrats, who have seen the Republicans recapture two Senate seats in 1978 and 1980, long ago despaired of ever beating Gov. Robert D. Ray, who has been there since 1968 and regularly rates over 70 percent in approval polls. But the Democrats have found what you might call a ray of hope in the return to the scene of their own vote-getting champion, former governor and senator Harold E. Hughes. Hughes retired from politics in 1974 after a single Senate term to do religious missionary work.

Now back in Iowa, Hughes has been unleashing his mighty baritone against the religious single-interest groups and suggesting strongly that he might be ready to run again. He was the last Democrat elected governor before Ray began his streak, and a Hughes-Ray contest would be a battle of the heavyweights.

Next door in Illinois, The Chicago Sun-Times reported last week, a private poll taken for former Democratic senator Adlai E. Stevenson III shows him running dead even with Republican Gov. James R. Thompson, each with 43 percent. Stevenson, who quit the Senate last year, has indicated his availability for the challenge to Thompson, who will be winding up six years in Springfield and seeking a third term.