During his "My Take," Tuesday, "Varney & Co." host Stuart Varney reacted to Trump selecting J.D. Vance as his vice president, arguing the Republican Party is uniting around the 45th president and his youthful running mate while Democrats remain divided behind an aging Biden.

: JD Vance strides into the Republican Convention.

He's Donald Trump's pick for vice president. He's 39. He's the Republican Party's future.

On the same night, President Biden was interviewed on NBC. He's 81. He's the Democrat Party's past. 

Quite a contrast. The future and the past. The young and the old. 

I found it painful to watch the president. He's too old for the job and he spent much of the interview trying to show he's still got it. 

He got feisty with his interviewer, Lester Holt. "Why don't you guys ever talk about the 28 lies Trump told?" 

So much for lowering the political temperature. 

Asked about his cognitive decline, he got testy again. He said "I've done 22 major events. My mental acuity has been pretty damn good." 

It was noticeable that our president spent virtually no time looking to the future and whatever vision he has for America. 

It was a defense of the past, which highlighted the difficulties of the present. 

JD Vance was something else. Some commentators have criticized his policies, but it wasn't policy that was on display last night. 

It was his youth and how long he's going to be shaping the Republican Party. 

If Trump wins this November, JD Vance will very likely be the 48th president. He would be in his 40s, just like John Kennedy when he took office in 1960.

Vance has three young children. Trump asked to speak to his 7-year-old and the young man was very happy. 

Imagine having youngsters in the White House again. 

Vance looks to the future, highlighting the opportunities of the present.

As of now, the Republican Party is united around Trump and his youthful vice president.

The Democrats are divided. It is the age and decline of their leader that is the problem.