While I think it makes sense for the Democratic Party to field a candidate against President Trump, all the evidence points to him being re-elected with a larger margin.

1. President Trump’s approval ratings while low, are fairly consistent with his ratings when he ran last time. He’s not lost much public support in the past four years.
2. The candidate the Democratic Party has fielded against him is essentially the same as the candidate that ran against him in 2016. There is little difference between Hillary Clinton and Joe Biden, they’re both centrist, career politicians who are of advanced age.
3. The economy is strong and inflation is low. While there are pockets of poverty and chances for things to go badly between now and November, the truth is for many Americans this is pretty good times, the best since the late 1960s.
4. Incumbents usually win re-election. The last president not re-elected was George HW Bush, he lost during a deep recession in 1992 to young, colorful governor of Arkansas. Bill Clinton was colorful and new at the time, something you can’t say about Biden.

That said, I think it’s worthwhile for the Democrats to put a opponent up against President Trump.

1. We have no idea what will happen between now and November. President Trump could do something that is incredibly unpopular or illegal and he could lose support of his base. He could have a heart attack and pass away. There is no guarantee that Trump will be a viable candidate come November, and the democratic nominee could be a fall back for the voters. You got to play to have a chance to win.
2. Running a candidate against President Trump gives the Democratic Party a chance to fundraiser and expand public knowledge of their policy proposals. It will allow them to show the public that they have good ideas too and to consider voting for democrats down ballot.
3. Running a candidate against Trump means the Republican Party will have to spend resources defending the president. This will divert attention of the GOP, allowing Democrats to focus on winning races down ballot, especially in the US Senate where combined control of the House and Senate could give the Democratic Party significant control of national policy with President Trump acting as a check with his veto pen. In exchange, Congress could investigate the president to ensure he’s remaining ethical.