Up Close: Many Republicans trying to stop Trump

NEW YORK (WABC) -- As Donald Trump continues to lead the pack in the Republican presidential race, he picked up the endorsement this week of New Jersey Gov. Chris Christie.

But many other Republicans are trying to stop him. Among them: Congressman Peter King, who is endorsing Marco Rubio.

I asked Rep. King about why he waited until now to back Sen. Rubio.

Also this week, there are so many tough decisions facing parents about raising their kids. One of the toughest, and most controversial, is do you let your child play tackle football?

An estimated 300,000 high school athletes every year suffer concussions.

And nearly half of them are suffered by high school football players.

Joining us is one of them, a 12-year-old boy from Manhattan. He wants to play tackle football, but his mother won't let him.

She also happens to be a pediatrician, and has seen far too many head injuries in kids.

The mother is Dr. Dyan Hes, who joins us with her son Dean Zilbeman.

Bill Ritter talks with Dr. Dyan Hes and her son Dean Zilbeman about the danger of concussions from playing football.

Finally, political consultant Hank Sheinkopf is with us to discuss the presidential campaign.

Bill Ritter talks with political consultant Hank Sheinkopf.