By the end of 2012 — the last year of President Barack Obama's first term — his administration had deported a record 1.5 million people deemed to have been residing in the country illegally.
That year alone, a total 225,000 of these immigrants — 55 percent of them convicted criminals — were sent packing, according to official figures.
This occurred as Obama talked of a path to citizenship for many others deemed law-abiding. If Democrats disliked the enforcement measures then, they didn't form a roaring chorus of national dissent.
Under President Donald Trump, however, mass deportations and border crackdowns got a bad name in more places. The president's approach brought to the fore the ugliness of family separations, less priority on criminality, and threatened cancellation of "dreamers'" protections, all in tandem with his nasty generalizations about those who come here.
Now Obama's two-term vice president, Joe Biden, is trying to win the Democratic nomination against Trump. Logically, this inspires his younger and lesser-known rivals on the crowded debate stage to try to seize a few seconds of desperately needed attention with aggressive sound bites zinging him.
If they can't dislodge Biden from Obama's record, they can at least safely pick at that record in retrospect. Mayor Bill de Blasio stood out as an example of this on Wednesday night in Detroit. Posing as the progressive champion, he loudly demanded Biden explain if he resisted deportation policies while in the administration.
Biden dodged, but de Blasio's gambit was clear. He was trying for a national replay of his local performance in 2013 — when he stood out in Democratic mayoral debates as the antagonist of front-runner Christine Quinn, the council speaker who had agreed on legislation and budgets with Republican Mayor Mike Bloomberg.
Not that the Democratic contenders would be trying to alienate Obama, who polls show remains popular among party registrants. But this early in the primary process, they are vying to win over progressive activists with positions everyone knows could change in mid-campaign.
Defend Obamacare? For a decade, left-wing critics thought the Affordable Care Act had been too closely crafted by the insurance industry. Even Trump issued such a criticism in 2016. The "Medicare for All" plan pushed by Sen. Bernie Sanders has a following, which explains its endorsement by other candidates this early in the process. So far the Trump administration has not expanded or improved coverage.
Of course, Obama's vow that "if you like your insurance plan, you can keep it" turned out to be a false pledge. Will that too be revisited as the insurance question is debated?
To some degree, even those who have won the nomination depart from the previous president of their party. By October 2008, the late Sen. John McCain (R-Arizona) was slamming GOP President George W. Bush's approach to the financial crisis.
And in 2016, Hillary Clinton, who'd been secretary of state, did an about-face and dropped her support for the Obama-negotiated Trans-Pacific Partnership, which was unpopular among labor unions.
Stay tuned for more policy shifting, with a year to go before the national conventions.