The Best-Laid Plans: Labor had its Solidarity Day, and the Republicans were supposed to have their Unity Day as well last week, a Sept. 15 celebration marking the first anniversary of the day in the 1980 campaign on which Ronald Reagan, George Bush and several hundred Republican members of Congress and candidates stood up and pledged what they would do together if they came to power. To everyone's surprise, they have done most of the things they said they'd do: cut taxes, trim the bureaucracy, boost defense, reduce congressional staffs. So a celebration seemed to be in order.

But the plans were put on ice, for an interesting reason. White House congressional liaison officials insisted that the guests of

West Virginia Gov. John D. Rockefeller IV reaches the end of his second term in 1984, and is ineligible to run for reelection. He is interested in a spot on the national Democratic ticket, but if that doesn't come through he is considered sure to seek the Senate seat now held by Democrat Jennings Randolph, who will be 82 when his term expires in 1984.

What intrigues West Virginians is the continued talk that the Democratic candidate to succeed Rockefeller might be Sharon Percy Rockefeller, now the state's First Lady. She is the daughter of Sen. Charles H. Percy (R-Ill.) and newly elected chairman of the board of the Corporation for Public Broadcasting, and she denied the rumors recently, but in language that left plenty of room for her to change her mind. Remembering the governor's free-spending campaigns for governor, West Virginia pols ask, "Can you imagine what a Rockefeller-Rockefeller ticket might bring in?"