Susan Collins is at the pinnacle of her career. She has more power, influence and exposure now than ever before. At a critical moment in American history, she arguably has more power to shape the health care of Mainers and Americans over the next generation than even the president has. How she uses that power will define her legacy.

Collins has had a long and distinguished career, with an outsized influence on national issues, as a moderate swing vote within the national Republican Party. But history has a habit of forgetting long careers and remembering pivotal moments. Like Margaret Chase Smith standing up to Joe McCarthy, when he was at the peak of power. And Bill Cohen’s vote to impeach Richard Nixon, or George Mitchell’s Irish peace deal.

In each instance, those leaders found the courage to step into the swirling protests, the pressure from all sides and the glare of the bright lights, to reveal both character and courage. And each did it when compromise and getting along were far easier paths to take.

Susan Collins now has the opportunity to join that small group of illustrious Maine leaders. A few months ago, Collins showed courage when she refused to endorse Donald Trump. In the weeks and months ahead, she will have two even greater opportunities to do so.

If the ongoing investigations of Russia’s influence in the last elections, of which she is part, lead to evidence of collusion between the Russians and the Trump campaign, she may be called upon to vote in an impeachment proceeding. But long before that, she will play a crucial role in whether millions of Americans, and tens of thousands of Mainers, will have health care next year.

The Republican Party is in desperate need of a victory in this Congress. Something to show the folks back home and crow about in the next election. And that desperation is leading them to a point where they seem ready to risk the hides of their constituents to save their own.

But Republicans are also in disarray on what to do about health care. The most conservative faction of the party wants the federal government’s role in health care, including in Medicaid, to shrink. A smaller and more moderate faction, that includes Collins, wants to improve on Obamacare but not force millions of people to lose their health care. The moderate group holds the pivotal votes in health care.

Susan Collins recently said that she wants “more people to have health care, not fewer.” The problem is that no Republican bill — either the one passed in the House or the proposal currently being floated in the Senate — can achieve that goal. That’s because health care costs money, and conservatives in the party will only vote for a bill that cuts funding.

Over the next few weeks, Republican leaders in Congress, and the president, are going to put out a snowstorm of soothing but senseless words about their health care bills. They’ll claim, as President Donald Trump did during the campaign, that we’re going to somehow have better health care and lower costs. And they’ll use a practiced straight face when they say it. But the math isn’t like politics. It doesn’t lie.

Beneath the fog of Washington’s war over health care is a deeper moral question for all of us. What kind of country to we want America to be? Do we want health care to be rationed on the basis of income, or class or a person’s station in life? Do we want to be the only modern economy in the world whose health care plan is essentially an updated version of survival of the fittest?

Say what you will about Obamacare. It needs to be improved. But it took action after a half century of gridlock and windbag speeches. It provided health care to well over 20 million Americans. It didn’t stop the rise of health care costs, but it slowed those rises. It’s something to build on. But any improvement on that bill has to move us forward, not backward.

This is what I hope for Susan Collins: That she will see through the spin. That she’ll endure the pressure of a party desperate for a victory, to the point of being indifferent to the human cost of their actions. That she will do the right thing for Maine people and for Americans across the country. And that she will protect not just the poor in Maine, but also working and middle class families who, if they lose their health care, can be suddenly destroyed by illnesses or hospitalization.

This is your moment to shine, Susan. Many of us are rooting for you.

Alan Caron, a Waterville native, is the principle of Caron Communications and the author of “Maine’s Next Economy” (2015) and “Reinventing Maine Government” (2010). He can be reached at: alancaroninmaine@gmail.com