It wasn't supposed to be as difficult for Hillary Clinton this time.  The nominating process was going to be a coronation – a stately march to the convention and victory for the first female president in history.

But something happened on the way to the royal wedding: the radicals in the Democratic Party found a candidate they could fully embrace.  Every time Clinton seeks to end this endless contest for the nomination, up pops Bernie Sanders and his legions.  So, following her huge victories in the east coast primaries last week, Hillary was expected to coast to victory in the decidedly un-radical state of Indiana.

Such was not to be.

Sanders ambushed Clinton in the Hoosier State, winning 52.5% of the vote to Hillary's 47.5%.  It was a drubbing that was as unexpected as it was unwelcome for the Clinton camp.  Even as she tries to pivot toward the November election and her showdown with Donald Trump, Sanders keeps pulling her back to the reality that the nomination is not quite hers yet and could still slip away.

Politico:

Less than a half hour after results began pouring in, Sanders rallied supporters in Louisville, Kentucky, where voters will head to the polls on May 17. Ticking through his standard stump lines while bashing Clinton for her paid speeches and 2002 vote in favor of invading Iraq, Sanders told a boisterous crowd that their ideas will prevail.

“I’ll tell you what is extremely exciting for me, and that is that in primary after primary, caucus after caucus, we end up winning the vote of people 45 years of age and younger,” Sanders said. “And that is important because it tells me that ideas that we are fighting for are the ideas for the future of America and the future of the Democratic Party.”

Clinton was not expected to deliver any remarks on Tuesday night. Her campaign announced she will speak in Washington Wednesday at a reception organized by the Asian Pacific American Institute for Congressional Studies.

The win bolstered Sanders' pledge to remain in the race through the Democratic National Convention in Philadelphia despite trailing in the overall and pledged delegate counts. Because Indiana allocates delegates proportionally, though, it will produce more of a psychic boost for Sanders and his supporters than an actual dent in Clinton's lead.

The calendar for the rest of May portends favorably for Sanders, as well, with West Virginia up next on May 10, followed by Kentucky and Oregon on May 17.

“I want to thank the people of Indiana for the great upset victory that they gave us tonight. This is the 18th state that we have won, and we expect more victories in the weeks to come," Sanders said in a statement released Tuesday night.

Sanders is favored to win those three contests, though none has a purely open primary, like in Indiana. Sanders has performed better in states where voters can vote in whichever party's primary they prefer, regardless of registration.

As Sanders alluded to, Clinton has enormous problems attracting any Democratic voters under the age of 45.  It is her hold on minority voters, and a healthy slice of white women, that is carrying her so far.  How that translates into victory in a general election will be key to who wins the White House.

Meanwhile, Sanders keeps on keeping on.  His fundraising has been down, and the pundits have largely written him off.  But he's about ready to go on another winning streak, which will strengthen his claim that superdelegates should switch sides and support him.

Given the hold Clinton has on the party, this is doubtful.  But outside events having to do with the FBI email investigation could still force the hand of party elders to replace her at the top of the ticket with Sanders.  It's all Bernie has right now, and he will play the string out until the end.