Although she insists her thinking has evolved via enlightenment on both issues, Gillibrand concedes that her original positions were formed in part by political calculation. In her memoir, "Off the Sidelines," she writes, "Previously, I had only looked at these issues through the lens of my small, rural upstate district which didn't suffer greatly from gun violence or families battling a broken immigration system to stay together."

Was she ignorant about these issues? Or, was she trying to heed her constituents’ wishes? It would be one thing for Gillibrand to advocate for, say, dairy farmers, since New York ranks fourth in the U.S. in milk production. But gun control and immigration reform are matters of such overriding national importance that one hopes any lawmaker would deal with them based on conscience rather than polling.

Gillibrand is by no means the only candidate with, as the political term of art would have it, baggage.

Sen. Bernie Sanders was praised by the NRA when he promised during his 1990 congressional campaign to vote against a mandatory waiting period for handgun purchases. Then, as a senator representing sparsely populated Vermont, he voted in favor of allowing guns on Amtrak trains and in national parks. Yet today candidate Sanders describes himself as a staunch supporter of gun control.

Clearly, guns are viewed differently in Vermont than in urban centers, and much has changed — even among progressives — after decades of gun violence. Yet it's fair to ask what Sanders really believes. His situation is a reminder than you can't fully escape from your record, and the longer you serve the more problematic that becomes.

Joe Biden’s views on abortion have evolved over his 50 years in government. Explaining his early anti-abortion votes, he told NBC in 2007: "I was 29 years old when I came to the U.S. Senate, and I have learned a lot." But unlike Sanders and Gillibrand, whose conflicted views are traceable to politics back home, Biden’s stance was rooted in his religion. "Look, I’m a practicing Catholic," he said, "and it is the biggest dilemma for me in terms of comporting my religious and cultural views with my political responsibility."

As the District Attorney in San Francisco, Sen. Kamala Harris was faced with taking positions that the very nature of her office seemed to mandate. After all, some say DAs are supposed to be "tough on crime." So, for example, she found herself prosecuting the parents of habitually truant children.

When she became state attorney general she argued against releasing prisoners to reduce overcrowding, and she moved slowly to investigate some shootings by California police. Now, as a senator and candidate for president, she maintains that she is "fighting to fix our broken criminal justice system."

The need to reconcile past positions must be especially frustrating for this season's crop of Democratic contenders. They seek to replace a president whose morning tweets are often in direct conflict with positions he takes later the same day. Trump managed to win in 2016 without ever having to acknowledge that many of his positions had changed, let alone explain why his stances on important issues seemed so blatantly based on politics rather than principle.

In assessing Democrats, voters are likely to be more forgiving when a candidate’s position shifts due to enlightenment on an issue rather than political calculation. But that's not an easy judgment to make. The policies being laid out by those seeking the presidency seem clear, yet the roots of those policies often appear tangled.

Kirsten Gillibrand cites the words of Eleanor Roosevelt: "Do what you feel in your heart to be right — for you'll be criticized anyway." For the rest of us, that leaves the difficult question of how to distinguish a change of heart from what is merely an opportunistic change of direction.

© Peter Funt. This column originally appeared in USA Today.