OnPolitics: We're back. So is Joe Biden.

We're back, OnPolitics friends, and so is Joe Biden: The ex-vice president best known for those Obama-Biden memes launched his presidential campaign tour on Monday. Now he's at the front of Democrats' 2020 pack due to his massive name recognition (thanks, Obama). But that means a target on Biden's back. Who's firing? President Donald Trump, who tweeted 60 attacks on Biden in under 20 minutes on Wednesday. That's just ... Wow.

Most Dems think Biden's the best pick to beat Trump, a new poll shows, but a lot of them (70%!) want Uncle Joe to beat on the issues — not Trump. What's Biden want, then? A $15 minimum wage, more taxes on the rich and a medicare public option, he told a crowd in Pittsburgh. And support for labor unions — a topic he battled Trump over on Twitter.

Don't expect the Trump-Biden bludgeoning to end soon. If the White House tries to block investigations swarming around Trump, Biden said this week, it would leave Congress "to the only other constitutional resort they have: impeachment."

Them's fighting words. Then again, Biden and Trump already said they'd "beat the hell" out of each other.

Yikes. Here's the rest of politics this week:

This week in Trump:

• Trump and his kids sued Deutsche Bank and Capital One to keep their finances from Congress

• Clinton asked Beijing: "China, if you're listening, why don't you get Trump's tax returns?" (A totally hypothetical question)

• Trump's attorney general, William Barr, backed him on Russia before a Senate panel, but refused to do so before House lawmakers

This week in 2020 Democrats:

• Kamala Harris's grilling of William Barr was a key moment in this Wednesday's hearing.

• Related: A slew of 2020 Democrats are now calling on Barr to resign

• A van crashing into a building cut short Corey Booker's Florida event

• Bernie Sanders has a plea: Let all felons vote — even those who worked for Trump

• $600? Kirsten Gillibrand wants to give it to you to spend on campaigns

• Michael Bennet, the Colorado senator, entered the 2020 race for president

• Nuclear energy could be making a comeback thanks to ... Democrats?

Until next Friday, OnPolitics friends. Thanks and have a great weekend. — Josh Hafner

This article originally appeared on USA TODAY: OnPolitics: We're back. So is Joe Biden.