Sometime in 1966, about the time his wife expressed amazement at his thinking, the light of dawn began to reach Sen. Birch Bayh (D-Ind).

What amazed the late Marvella Bayh was that her husband, who had just become chairman of the constitutional oppose the idea of direct election of presidents.

Bayh looked it over, gave it some thought and became a convert. From his forum as chairman of the Senate Judiciary subcommittee. He became the No. 1 champion of a constitutional amendment to abolish the electoral college and directly elect presidents and vice presidents.

Thirteen years have passed, Bayh is till the No. u champion of direct election and no issue has been debated more and remained still unresolved on the Senate calendar.

To get an idea of how the time has gone, consider this: while the debate on direct election has ebbed and flowed, Bay's subcommittee has started four other constitutional amendments on their way to ratification by the states.

Two, the 18-year-old vote and presidential succession, have been ratified. Two others, the Equal Rights Amendment and District of Columbia congressional representation, remain pending.

But the Senate now appears to be closer than ever to a final vote on the direct-election amendment, although the outcome, by Bayh's estimate, is till very much up in the air.

A first order of business after the Senate returns from its recess this week will be Tuesday vote on Bayh's cloture petition, a move to cut off lenghty floor debate that went on intermittently last month.

If cloture is onvoked and other possible amending tactics thwarted, a final vote on direct election could occur before week's end.