3 former vice president joe biden has officially entered the race for the democratic nomination to be president.the vice president enters the race already leading in polls.but as nikole killion reports, but with a large and diverse field of candidates, nobody is a shoe in yet.

3<former vice president joe biden made it official this morning...(nats)"i'm announcing my candidacy for the president of the united states."(track 2) much of the video focused on the race riots in charlottesville which a source close to biden tells cbs news.

Was when he decided to run.(sot: vice president biden)"the president of the united states assigned a moral equivalence between those spreading hate and those with the courage to stand against it.

In that moment, i knew the threat to this nation was unlike any i had ever seen in my lifetime."(standup: nikole killion/cbs news/the white house) biden's video apeared more like a general election campaign than a race for t primary.

He went after president trump - not any other democrat.(sot: vice president biden)"if we give donald trump eight years in the white house, he will forever and fundamentally alter the character of this nation, who we are.

And i cannot stand by and watch that happen."(track 3)(gfx) president trump punched back on twitter calling him "sleepy joe" and warned the vice president not to over look his primary campaign saying: "it will be nasty - you will be dealing with people who truly have some very sick & demented ideas.

But if you make it, i will see you at the starting gate!"(gfx) biden joins one of the largest and most diverse field of primary candidates ever assembled.at 76, biden is one year younger than 77-year-old bernie sanders.

South bend, indiana mayor pete buttigieg is the youngest democratic candidate at 37.

Nikole killion, cbs news, the white house.> 3 vice president biden will hold a fundraiser in philadelphia tonight with a campaign rally in pittsburgh on monday.