What to watch in tonight's debate

President Trump will try to break Joe Biden's composure by going after his son Hunter and other family members in tonight's first presidential debate — a campaign source tells Axios "nothing will be off the table" — while Biden plans to stick to the economy, coronavirus and new revelations about how Trump avoided paying taxes.

Driving the news: Biden and Trump are set to debate at 9pm ET at Case Western Reserve University in Cleveland, and it will be moderated by Fox News' Chris Wallace.

The big picture: Most voters' minds are already made up and early voting already has begun, so it's not clear how much of an impact this year's debates will have on balloting.

• But questions about absentee ballot rejection rates, turnout, litigation — and the history of Trump's narrow 2016 Electoral College win — are keeping the stakes high.

What we're hearing: Democrats want Biden to be the adult in the room, focus on the issues and show viewers the sense of leadership that Democrats say the country is craving right now.

• That may be easier said than done given Biden's history of getting defensive and flustered when his family is attacked. Biden's senior advisers want him to do everything he can to ignore Trump's anticipated jabs.

But Trump has his own plans. “Expect the president to prosecute the case against Joe Biden partly by using his son Hunter and brother James as his cudgels," a campaign source told Axios. "Nothing will be off the table and the president has dove into all of their activities.”

• Asked by reporters how Biden would respond to attacks about Hunter, senior adviser Symone Sanders said, "Voters don’t want to hear President Trump rehash attacks about Vice President Biden and his family."
• Biden deputy campaign manager Kate Bedingfield told reporters, "We're not gonna play this game. This is an incredibly serious moment for our country, and the American people need a serious president who can get us out of this mess that we're in because of Donald Trump."

Biden's campaign released his 2019 tax returns hours before the debate, in an effort to contrast his own history with revelations from an in-depth New York Times investigative report on Trump's tax returns — and to argue Biden is better for the working class.

• A Fox News poll released last week showed Biden leading by 1 percentage point with Ohio voters, but Trump leading by 5 on who voters trust to handle the economy.

Go deeper: See Kamala Harris and Biden's tax returns