In comments to supporters who were booing his plea to back Hillary Clinton for president, Bernie Sanders tried to put the situation into mature perspective.

"Brothers and sisters," he said to the crowd this morning, trying to calm them, "this is the real world we live in."

Some of his supporters, at least in that room, would prefer not to live in that world.  They would prefer not to consider the consequences of decisions that might lead to the election of Donald Trump, as if that is somebody else's responsibility. They could not be more wrong.

In the 2000 election, you may recall, some people justified their support for third-party candidate Ralph Nader by arguing that in the end, it wouldn't matter whether Al Gore or George W. Bush won the presidential election, that what mattered was making a statement.  Bush's subsequent narrow victory, followed by the invasion of Iraq, the deregulation of Wall Street, the 2008 Great Recession and stonewalling progress on issues such as climate change and gay rights, demonstrated the foolhardiness and short-sightedness of that position.

And while I was and remain no fan of President Bush, the difference between him and Trump is so enormous that it's hard to get your head around it.

I'm also not sure that this morning's events offer a true indication about the state of unity within the Democratic Party.  The Sanders supporters in that room and out in the streets of Philadelphia are not representative of Sanders supporters overall. They tend to be younger, more activist, more vocal, more idealistic and closer to revolutionary than most of those who cast primary ballots on behalf of Sanders. They are also much less likely to be serving as delegates to the actual convention.

So we'll see what happens tonight, when Sanders addresses the convention. The chances that he'll pull a Ted Cruz, ostentatiously refusing to endorse the person who defeated him, is nil. He has said earlier that "I intend to do everything I can to make certain (Clinton) will be the next president of the United States," traveling to "every corner of this country" to spread the message that she is "far and away the best candidate."

It'll be interesting to see how he drives that point home tonight.