Opinion by Paul Callan

(CNN) -- History will record that Joe Biden won Tuesday night's debate by demonstrating one important thing: he is not senile.

Over the past 47 months, President Donald Trump's unorthodox, undignified, and downright nutty behavior has exhausted the entire nation. Americans wake up each morning wondering what kind of bizarre claims and insults have been posted on the President's Twitter feed. Even those who agree with many of Trump's policies, including Republicans, are worn out and offended by the President's unpresidential behavior.

Former Vice President Biden's most important job in the debate last night was to demonstrate that he is a calm, professional, and entirely sane alternative to Trump. He clearly demonstrated those traits while Trump ranted, raved, and interrupted all attempts at rational discussion. The debate will be remembered not for the policies debated, but rather for the President of the United States acting like an angry, out of control toddler whenever any attention was directed toward his calm and dignified opponent.

The nation is ready for an alternative, an anti-Trump who will give us all a break. The minimal qualification, though, is that the Trump alternative must be of sound mind.

Prior to last night's debate the Trump campaign had been furiously pushing the notion that Joe Biden was running a "basement" campaign and could speak coherently only with the assistance of a teleprompter because he is senile.

In a Tuesday appearance on the Fox News, Rudy Giuliani, the President's personal counsel, claimed without any proof that many "doctors" had advised him that Biden had demonstrated clear symptoms of dementia and was probably taking medication to improve his performance.

Prior to the Tuesday debate the President had also suggested that both candidates should be drug tested. Both he and Giuliani were clearly saying that a doddering "Sleepy Joe" would be unfairly pumped up by drugs during the debate in the absence of a drug screening test.

By evening's end, a cynical person might suggest that the only person in need of drug therapy was Donald Trump. Calming Trump down would provide a welcome respite for the nation during the remainder of the campaign. And it is a relief to know that there is at least one calm and sane candidate in the field.