Bernie Sanders endorsed Hillary Clinton earlier this month, and reiterated his support for her again at the Democratic National Convention on Monday night. Ted Cruz, on the other hand, didn't even endorse Donald Trump during the Republican National Convention, usually a precondition for a primetime speech.

And yet, it was Sanders' supporters who angrily erupted at their convention, protesting loudly and sometimes profanely, while Cruz backers and an assortment of #NeverTrump delegates confined themselves to a few ineffectual parliamentary procedures that Republican leaders mostly ignored.

Sanders supporters in Philadelphia chanted "Lock her up!" when Clinton's name came up — just as Trump backers did in Cleveland. Some Sanders delegates went so far as to boo their own candidate, screaming "Take it back!" when he repeated his Clinton endorsement at a rally earlier in the day.

What gives? The Democrats gave over most of the first night of the convention to Sanders, politicians who had endorsed the Vermont senator during his primary campaign, and progressive figures like Elizabeth Warren who appeal to his followers — and even some of them, particularly Warren, got yelled at.

By contrast, Cruz was reprimanded by his own state delegation, including some of his own supporters, for not endorsing Trump. Imagine if the convention had devoted a night to constitutional conservatives, all of them expected to endorse rather than criticize Trump the way the progressives did with Clinton.

The ideological differences between Sanders and Clinton are obviously significant, a fact driven home not only by her paid speeches for Goldman Sachs but the fact that she is being nominated in an arena named after Wells Fargo. But the philosophical divide between Cruz and Trump is arguably bigger, and Clinton never insulted any members of Sanders' family.

Trump and the Republican National Committee were nevertheless able to bring Cruz dead-enders to heel more easily. The bottom line is that most Cruz delegates were party people, even if they weren't exactly establishment Republicans. And movement conservatives have labored within the GOP for decades even if they've rarely attained the level of influence they desire.

It is harder to tear down something you had a hand in building even if you aren't completely satisfied with the design.

Many, though certainly not all, of the most ardent Sanders supporters at the Democratic convention are new relatively new to the process, or they were longtime activists and protesters. Their expectations were unrealistic, and Sanders was a rare politician who inspired them. Some still believed, against all odds, that Sanders could be the nominee if he just fought hard enough for it.

Some #NeverTrump Republicans entertained similar illusions, but it was obvious that most of the grassroots had reconciled themselves to Trump, however unhappily, weeks before the convention. Cruz dropped out in May. Sanders pretended he was still in some meaningful sense running for president even after endorsing his opponent in July.

Sanders himself had never really run for office on the Democratic line before, campaigning instead as an independent or as the nominee of tiny progressive and even socialist third parties. He's caucused with Senate Democrats to gain influence on committees and he ran in the 2016 Democratic primaries to get a larger audience for his views, like when Ron Paul ran for president in 2008 and 2012.

The center-left Democratic Party of Bill and Hillary Clinton is not the diehard Sanders voters' creation. It is merely a vehicle for their "political revolution." Some of them don't think that revolution will necessarily be further by another presidential candidate.

Finally, the convention kicked off right after WikiLeaks exposed the extent to which the Democratic National Committee really was in the tank for Clinton, confirming the Bernie boosters' worst suspicions all along. Is Debbie Wasserman Schultz's scalp really adequate compensation?

It's not clear how many people the most vocal Sanders delegates really speak for. Polls show the vast majority of Sanders voters coming home to the Democratic nominee. Some will vote for Green Party nominee Jill Stein and presumably other options. Even Trump wants to make a play for Sanders voters. He has mocked Sanders for giving into Clinton at every turn. He mentioned Sanders twice in his acceptance speech at the Republican convention, Cruz zero times. He always brings the Democratic primaries into his jeremiads against the "rigged system."

The Republican nominee can win some of the less ideological anti-Clinton Sanders voters in Appalachia, as well as some of the union members in places like Michigan. But the number of truly progressive Sanders people who will vote for Trump just to spite Clinton is vanishingly small.

But the number of truly progressive Sanders voters who needed to get some pent-up rage against Clinton and the Democratic leadership out of their system is much larger and, we've learned, louder.