There are many reasons for Democrats to feel confident about the 2020 US presidential election.
Their voters are motivated and angry, as they showed in 2018.
Despite low unemployment and healthy economic growth, President Donald Trump's approval ratings remain stuck in the low 40s.
His presidency is, generally speaking, a rolling dumpster fire.
Polls show nearly all the prospective Democratic candidates leading him in head-to-head matchups.
But what Democrats may not fully appreciate - or at least may be inclined to push from their minds - is a series of factors that lay largely outside their ability to influence, and which will all put a thumb on the scale for Trump.
What they add up to is the equivalent of a hundred-metre dash where this president will get a 5m head start.
They won't guarantee a Trump victory, but they will mean that the Democratic candidate is going to have to run a vastly superior race in order to win. Let's dive in:
1) The Electoral College.
This most basic factor is probably the most important. In two of the last five elections, the Democratic candidate got more votes but the Republican candidate wound up in the White House. In 2016 Trump lost by three million votes but became president. No other country in the world has this absurd system, and for the foreseeable future it will always work to the Republican's advantage. It is entirely possible that once again Trump could be victorious because of some well-distributed votes while the Democratic nominee has the support of a majority of the electorate.
2) A weaponised federal government.
As the Mueller report (and his own public comments) make clear, Trump believes the federal government exists to serve him and protect him. He was already caught dispatching Rudy Giuliani to pressure Ukraine to open an investigation he thought would be embarrassing to Joe Biden. Does anyone think that if Trump orders Attorney-General William Barr to do the same in the US to the Democratic nominee, Barr will say, "I'm sorry, sir, that wouldn't be appropriate"? There are surely ways Trump plans to use the government to advance his re-election bid that we haven't even thought of yet.
3) Help from Russia, or some other country.
US intelligence agencies keep warning that Russia has plans to "meddle" or "interfere" in the 2020 election, but we rarely call their 2016 activities what they actually were: An attempt to help Trump get elected. Whether you think that's because Vladimir Putin thought he could get better policy outcomes from a Trump presidency or because he just wants to sow chaos, there's no reason to think he doesn't want Trump to stay in office for another four years. Given how much Putin got out of a relatively small investment last time, why wouldn't he mount a similar effort in 2020? Meanwhile, Trump has made it clear that he thinks he did nothing wrong in accepting Russia's help in 2016 and he'd be happy to have more of it. If any other country wants to pitch in - say North Korea - he'll welcome that too.
4) Social media disinformation.
While the left is perfectly capable of spreading falsehoods and hoaxes on social media, there's little doubt that the right is just more enthusiastic and organised about it at this point in history. Helped by Russian troll farms, you just never know what they might be able to inject into the information bloodstream. As Jim Rutenberg of the New York Times said, "When it comes to disinformation, all signs point to a 2020 campaign that will make 2016 look like a mere test run."
5) Voter suppression.
In state after state, Republicans have worked hard to erect barriers to voting for those who might be more likely to vote for Democrats: Voter ID laws, cutbacks to early voting, aggressive purges of voter rolls, and laws meant to discourage voter registration drives, among other things. There's no telling exactly what the magnitude of the effect of these suppression efforts will be in 2020, but they all work to Republicans' advantage, and they could be enough to swing the result in a closely-fought state like Wisconsin or North Carolina.
6) Fox News.
The network already acts as a propaganda organ for the White House, and as the election heats up they'll kick things into high gear, providing an endless stream of praise for Trump and slander of his opponent. In doing so they'll amplify every new Trump lie and convince the mainstream media to pay attention, making sure that the message penetrates beyond their narrow audience. While there are liberals on television, there's nothing on the left that compares to Fox's focus and influence.
7) The rest of the media.
When major news organisations are writing "Trump delivers new biting nickname to Democrat" stories, you know that they haven't learned nearly enough from the four years since Trump first became a candidate. There is simply no doubt that Trump will succeed in leading the media to ignore important issues in favour of covering whatever outrageous thing he says or whatever slanderous new charge he makes about the Democrat.
Put all these factors together and we could be looking at a repeat of the challenge Democrats faced in 2018 in their effort to take back the House.
It wasn't enough for them to have more support for the public; because of the structural advantages Republicans had, Democrats had to win by a huge margin in order to have a chance to seize control of the chamber. They managed it, winning the overall popular vote by a 9-point margin, or nearly 10 million votes.
Democrats may not need that wide a victory in order to defeat Trump next year. But just having the support of more Americans is not going to be enough.