The defense in the case of Charles E. Neiswender, accused of abstructing justice by allegedly soliciting a bribe from the chief defense attorney in the political corruption trial of Maryland Gov. Marvin Mandel, rested today without presenting and evidence.

When the jury returned to the courtroom late this morning the judge had heard nearly eight hours of legal arguments yesterday and today out of their presence, defense attorney J. Frederick Motz told them that Neiswender had decided against taking the stand.

"The defendant is persuaded that the government has not proved its case. The defense has no evidence to present and it rests," Motz said.

Motz had earlier asked Judge Frank A. Kaufman to acquit Neiswender. He argued that even if his client had solicited a $20,000 bribe from Arnold Weiner, Mandl's chief defense attorney, saying that he knew a juror who would fic the case for a price, that act did not constitute obstruction of justice.

Neiswender could have been conning Weiner, otz and his colleague Charles M. Kerr argued - and an attempted flim-flam of a defense attorney is not necessarily obstruction of justice, they said.

In response to this argument, Assistant U.S. Attorney Barnet D. Skolnik read from a sworn statement Neiswender made after his arrest Nov. 5, in which he said that he was paid $5,000 "to throw a snag in the Mandel trial." Skolnik said that statement refutes the idea that Neiswender was pulling a con job on his own.

Neiswender is the second man to be tried on charges of obstructing justice in the Mandel case. The first, Baltimore-area furniture salesman Walter Weikers, was convicted earlier this month of attempting to bribe a Mandel juror whom he was related by marriage.

A mistrial was declared in the Mandel case Dec. 7, after several jurors overheard a news bulletin about the tampering attempts.

Almost all of today's court session in the Neiswender case was consumed by protracted arguments in Judge Kaufman's chambers on the legal instructioin that the judge will give to the jury. Final arguments in the case are expected Saturday.