Now, there apparently will be another wrench thrown into the 2020 campaign cycle: the possible entrance of billionaire, political activist and former NY mayor Michael Bloomberg.
The ex-New York City mayor had reportedly been speaking with prominent Democrats over the past few weeks and expressing concerns about the prospects of former Vice President Joe Biden's campaign and liberal Massachusetts Sen.
The Alabama angle may seem unexpected - it's a ruby-red state that is unlikely to play a major role in the election - but it's the state with the earliest filing deadline.
"If we conduct, we're convinced we could win in nations voting on Super Tuesday and beyond, at which we'll begin on an even footing", Bloomberg adviser Howard Wolfson said in a statement reported by the Washington Post.
"He is in", Mr Vilsack said of Mr Bloomberg's message.
Bloomberg would face other challenges as well, particularly scrutiny of his three terms as mayor. "But there is zero evidence that rank-and-file voters in the early states of Iowa and New Hampshire feel the same".
In February next year, primaries and caucuses or state-by-state votes, will be held to pick a Democratic presidential nominee. He doesn't need voters to like him - he just needs them to hate Trump.
President Donald Trump is responding to a possible run by former New York City Mayor Michael Bloomberg for the Democratic presidential nomination, saying "There is nobody" he'd "rather run against".
Trump said Bloomberg "doesn't have the magic to do well", and alleged he has "some personal problems".
But in a statement Thursday, his political adviser Howard Wolfson says Bloomberg is anxious that the current crop of Democratic presidential candidates is "not well positioned" to defeat President Donald Trump.
For one thing, Trump only spent $66 million of his own money on winning the presidency - a large sum, but inconsequential in comparison with the $2.4 billion spent on the race in total.
So while Bloomberg will be a longshot in the race, it will be interesting to see if he can gain momentum and angle towards a showdown with Trump.
Among those Bloomberg has reached out to is Tom Vilsack, the former Iowa governor who remains popular in the state. But he is expected to file to get on the ballot in Alabama's presidential primary.