WASHINGTON — Former Vice President Joe Biden, in launching his third presidential bid on Thursday, articulated what should be on the top of Democratic voters shopping list as they decide whom to support in the 2020 primary.

The only factor in evaluating the now 20 contenders is who can beat President Donald Trump.

Biden didn’t waste time in getting to the bottom line.

“If we give Donald Trump eight years in the White House, he will forever and fundamentally alter the character of this nation. I cannot stand by and watch that happen,” Biden said in his announcement.

“Our core values, our very standing in the world, our democracy, and everything that makes us who we are is at stake.”

I have no idea at this early stage if Biden is the one who can beat Trump. Trump wins if the Democrats destroy each other in the primary and don’t find ways to speak to Trump voters.

If you are a Democrat, my analysis is if you want to win the White House back, don’t get caught up in ideological purity tests.

In the 2008 Democratic primary, Barack Obama attacked Hillary Clinton because her health-care plan forced everyone to buy health insurance, with a penalty if you don’t.

The mandate and penalty Obama belittled successfully in the primary became — surprise! — a cornerstone of his signature Obamacare health-care plan.

The takeaway is that both Clinton and Obama wanted to get more people covered by health insurance if they were president. They agreed on that.

Obama didn’t try for a “Medicare for All” system because at the time his team didn’t think it would work and could never get it passed.

Now, years, later, “Medicare for All” is part of the Democratic primary conversation.

For Democrats who care about health-insurance coverage, climate change, student loans, taxes, abortion and LGBTQ rights, job creation, tax equity, reparations, voter suppression and other issues, these policies advance in 2021 only with a Democratic president.

Chicagoans connected to 2020 presidential campaigns

•One of Biden’s national surrogates will be Sheila Nix, who served as chief of staff to Dr. Jill Biden from April 2013 to Jan. 20, 2017, the last day in office. In the 2012 Obama/Biden re-election campaign based in Chicago, Nix was chief of staff for Vice President Biden.

Nix leads the Chicago-based Tusk Montgomery Philanthropies.

•Sen. Amy Klobuchar, D-Minn., named the Evanston-based direct mail guru Pete Giangreco as a senior adviser.

•South Bend Mayor Pete Buttigieg tapped Chris Meagher to be his National Press Secretary. Meagher was a spokesman for Cook County Board President Toni Preckwinkle’s mayoral campaign.

Buttigieg and Invest to Elect Illinois

I reported earlier this week that Buttigieg was headlining two high-end fundraisers for his campaign on Tuesday in Chicago and Evanston. He also did an event hosted by Invest to Elect in Glencoe, where he was interviewed by Invest executive committee member Carol Dawley.

Invest to Elect is finding its niche as an Illinois donor group: It’s not for small donors who give on the web nor for the bigger players who have thousands of dollars to contribute at a single fundraising reception.

Invest organizes meet-and-greets like the one in Glencoe for its members — who pledge to donate $3,000 to federal candidates. Folks donate on their own; bundled together, they flex their collective political muscle.

Besides Buttigieg, former Obama HUD Sec. Julian Castro met with the group when he was on a Chicago swing on April 16; Klobuchar’s turn was on March 18.

Another Republican in race to defeat Underwood

First-time candidate Ted Gradel announced his bid in the GOP 14th Congressional District primary, joining an emerging field of Republicans who want to defeat freshman Rep. Lauren Underwood, D-Ill.

Gradel, an independent investor from Naperville, kicked off his campaign highlighting his football career at Notre Dame. Famed Notre Dame coach Lou Holtz vouched for Gradel in his announcement video.

Gradel told me he will be funding his campaign with a combination of individual donors and his own money.

State Sen. Jim Oberweis, R-Sugar Grove, and family members provided most of his first-quarter fundraising. Oberweis, who has bankrolled previous campaigns for Congress and the Senate, loaned his campaign $100,000; he raised $106,450 from individuals, including $2,800 each from James, Joe, Ashleigh, Julie and Trish Oberweis.