Can lame duck Biden continue in office till January?

Key decisions will need to be taken in the coming months over arming Ukraine and the future of the Middle East

The response of senior Republicans to Joe Biden’s decision to withdraw from the presidential election was that he should also stand down from the White House. Mike Johnson, Speaker of the House, said: “If Joe Biden is not fit to run for president, he is not fit to serve as president. He must resign the office immediately.”
Were he to do so, his vice-president, Kamala Harris, would step up for the coming months and challenge Donald Trump as an incumbent in November, albeit one briefly installed. That would also require her to secure the Democratic nomination which, although likely, is not yet sewn up.
Would Mr Biden’s resignation help or hinder Ms Harris’s ability to defeat Mr Trump? We are unlikely to find out because it took the President such an inordinate length of time to decide to pull out of the election. The chances of him leaving the scene entirely are slim. Yet it means America will have a lame duck leader for the next few months when key decisions need to be taken over help for Ukraine and the future of the Middle East, with Benjamin Netanyahu, the Israeli leader, in Washington for talks.
Mr Biden will say he has the experience to deal with these matters, but it is legitimate to question whether he is up to the task at all anymore and might be better advised to step aside. As head of state, he can delegate much of his work to his ministers and officials. But he also has a critical constitutional role to play as commander-in-chief of the Armed Forces. 
If his faculties have deserted him, his advisers should be honest enough to admit it and not protect him as they have done for months now, with disastrous results.