Why did the Nixon administration try to stop publication of the pentagons papers?

The administration argued Ellsberg and Russo were guilty of a felony under the Espionage Act of 1917, because they had no authority to publish classified documents.

he believed that congress would be better not dealing with "lobbyists", or people who seek to influence (a politician or public official) on an issue, since historically, they had problems with these kinds of people. he thought lobbying produces benefits, but should be carefully monitored.