Former Vice President Joe Biden’s appearance at a Martin Luther King Jr. Day breakfast gathering on Monday in Washington underscored that a potential presidential candidate’s advantages and disadvantages are a matter of context and history.

Biden’s tough-on-crime history and chairmanship of the Senate Judiciary Committee were positives when Barack Obama was shopping around for a VP. In 2019, Biden actually apologized, albeit obliquely, for his past record. “You know I’ve been in this fight for a long time. It goes not just to voting rights. It goes to the criminal-justice system,” Biden said. “I haven’t always been right. I know we haven’t always gotten things right, but I’ve always tried.” His support for the 1994 crime bill will be a sticking point with progressive voters should he run for the Democratic nomination; if he makes it to the general election, it will be a powerful weapon against President Donald Trump — who talks tough but has smeared the FBI, used border control agents to rip kids from their parents’ arms, tried to punish cities that wanted to focus on violent crime and community relations rather than immigration roundups, and joked about police misconduct.

Biden’s an old white guy (like another possible contender, Sen. Bernie Sanders of Vermont). Will that help him with Rust Belt voters who went for Trump in 2016 or hurt him with the diverse Democratic electorate in a year in which female, African-American and Hispanic candidates abound? Biden made sure on Monday that everyone knew where he stood on civil rights: “There’s something we have to admit — not you — we, white America, has to admit, there’s still a systematic racism and it goes almost unnoticed by so many of us.” He warned: “We’ve learned in the last two years, it doesn’t take much to awaken hate, to bring those folks out from under the rocks. That part of American society has always been there. Will always be here. But has been legitimized.”

Biden’s perceived foreign-policy experience was a plus in his column when he was under consideration for VP. Now, however, he might be burdened by the mistakes of two presidents — support for the war in Iraq, inaction in Syria, premature pullout in Iraq and insufficient responses to China’s economic, cyber and territorial threats. A younger generation of Democrats will be able to duck responsibility for most of those, claiming — as Obama did — that their better “judgment” makes up for lack of national security experience.

Biden will be a tough campaigner, well-funded and aided by top-flight advisers. He knows everyone there is to know in the Democratic Party and has the experience of running at the presidential level. Once again, however, all those qualities might remind voters of ultimate insider and lifetime politician Hillary Clinton. Moreover, Clinton, when running against Sanders for the nomination, wasn’t the oldest or oldest-looking candidate in the field. Should Biden run, he’ll have to stifle any whiff of “inevitability” (another Clinton handicap), but he’ll also face the unenviable task of competing against a fleet of younger, fresher faces.

No candidate in the large and growing field of Democratic candidates has an easy path to the nomination. Biden might have the most pronounced advantages as well as the most serious disadvantages. With Biden in the race, the question front and center for Democrats will be: Do they reach into the past for a skilled insider to clean up Trump’s messes, or do they flip the script on Trump and find someone who is going to fight corruption and the status quo, which Trump failed to vanquish?