This is CNN breaking news.

Welcome to the lead. I'm Pamela Brown and for Jake Tapper and we begin with big breaking news.

Any minute now, we will see a history-making moment.

Joe Biden and his new running mate Senator Kamala Harris

together for their first joint campaign event

in Wilmington, Delaware, effectively launching the

2020 Democratic ticket. Their spouses, Joe Biden and Doug

Emhoff are also expected to be there and it comes as we learned Biden long believed Harris was the strongest choice for the job.

sources tells CNN.

Biden publicly acknowledged the close friendship that Harris had with his late son

Bow that helped guide his decision.

And Harris, one source says, spoke at length about their friendship

in her interview with Biden's search committee.

I want to bring in CNN's Jeff Zellini and Jeff as we wait for

this event to begin you're learning more about that intense 10 days before

Biden made his final decision on Senator Harris as his running mate.

Pamela we are and it's clear that California on Senator

Kamala, we are and it's clear that California Senator Kamala Harris was anticipated

and viewed by most Democrats inside and outside the process as the person to

beat essentially in this is the one going into this

competition if you will this vice presidential a search with the most experience the

national campaign experience someone who had legislative experience of course had executive experience experience,

...