Realistically. No viable candidate wants to lose, and they will likely lose against Clinton. Her support is just too strong this time compared to 2008.
They've looked at the past and current data and realize realistically, they would likely lose.
Biden really really wanted to run, but he isn't. If they thought they had a chance both Warren and Biden probably would have ran.
Good luck beating the Clinton machine.
In 2007/2008 Obama had to make up a 15 point or so deficit against Clinton.
Bernie has to make up a 40+ one.
Clinton was never polling over 50% in 2007/2008.
Clinton is now polling close to 60%. And no "scandal" has changed this.
Obama was one of the most gifted politicians we've had in a generation or more.
Bernie is no Obama.
Obama was also able to match or beat the Clinton $$$$
Bernie is nowhere near that.
Hillary was considered by most to have run a very mismanaged campaign.
Now Hillary has hired many of the Obama people that beat her.
Good fucking luck beating the Clinton machine.
Obama BARELY did himself back in 2008 even with all those advantages.
Take a look at these final 2008 numbers.
^ Look at those final numbers. Those are SCARY for anyone that doesn't have Obama's hype or skills. And realize Clinton is in a MUCH stronger position now.
So don't be surprised when the Clinton machine wins the Democratic primary in 2016. They almost did against Obama in 2008.