A little more background...
During his confirmation hearing, when asked by Senator Al Franken “if there is any evidence that anyone affiliated with the Trump campaign communicated with the Russian government in the course of this campaign, what will you do?," Sessions replied, “Senator Franken, I am not aware of those activities … I didn’t have – did not have communication with the Russians.”
The only way for Americans to be able to trust that our government can act with integrity -- to know that our top leaders aren't compromised by a foreign power, and to trust that the nation's top cop follows the law that he is duty-bound to enforce -- is for Attorney General Sessions to resign his post immediately and for his successor to appoint a special prosecutor to begin a comprehensive investigation of Donald Trump, his campaign, and his administration.
Anything short of that puts our country's security, our free and fair elections, and our justice system at grave risk.
And for your viewing pleasure, here is a video from 1999: A younger Jeff Sessions stating the importance of prosecution for perjury.