He challenged de Klerk to hold a whites-only election.
It is also an acknowledgment on his part that he could no longer win a whites-only election because of his dwindling support among whites.
He won many other important civil rights cases, including a challenge to the whites-only primary elections in Texas.
South Africa holds its whites-only parliamentary elections May 6.
An anti-apartheid Defiance Campaign had been announced in the run up to the whites-only general election.
An extraordinary event took place before the whites-only parliamentary election in May.
If he loses, he has promised to resign and do battle in another whites-only election.
It was the first move by liberal whites inside and outside Parliament since the whites-only election was held in May.
The Conservatives more than matched gains they made in last year's whites-only election for Parliament.
The raid came hours after the labor group backed a nationwide two-day peaceful protest to coincide with the whites-only general election next Wednesday.