18 U.S.C. § 1621 : US Code - Section 1621
Whoever -
(1) having taken an oath before a competent tribunal, officer, or person, in any case in which a law of the United States authorizes an oath to be administered, that he will testify, declare, depose, or certify truly, or that any written testimony, declaration, deposition, or certificate by him subscribed, is true, willfully and contrary to such oath states or subscribes any material matter which he does not believe to be true; or
(2) in any declaration, certificate, verification, or statement under penalty of perjury as permitted under section 1746 of title 28, United States Code, willfully subscribes as true any material matter which he does not believe to be true; is guilty of perjury and shall, except as otherwise expressly provided by law, be fined under this title or imprisoned not more than five years, or both. This section is applicable whether the statement or subscription is made within or without the United States.
During the hearings before a Senate Committee regarding his nomination to be Attorney General, Jeff Sessions broke federal law. He had sworn to tell the truth, but lied to the committee -- telling them he had no contact with Russian officials during the campaign, even though he had two such contacts (at least). That is perjury.
What would happen to you or I, or any ordinary citizen, if we lied under oath to Congress? We would be heavily fined or sent to prison for up to 5 years, or both. And that's what should happen to Sessions. He has recused himself from investigations regarding the links of the Trump administration to Russian officials, but that's not good enough.
This is a nation of laws -- and no person is above those laws (not even the president or other government officials). Sessions should be treated like any other American citizen would be treated. He should be charged with a crime and indicted for breaking federal law -- then tried before a jury of his peers. And he should, at the very least, resign from his job as Attorney General. We should not have a lawbreaker occupying that important office.