U.S. Sen. Amy Klobuchar has well-earned the Star Tribune Editorial Board's endorsement for a third term. In an institution that prizes seniority, she is a prime example of how a lawmaker can grow in stature and breadth over time. Throughout her Senate career, Klobuchar has laid the foundation for strong bipartisan relationships among her colleagues.

Thoughtful, respectful and respected, Klobuchar has a demonstrated ability to work with both sides that continues to pay dividends for herself and Minnesota. That's why even in the minority, Klobuchar was the lead Democrat on 20 bills passed during the Trump presidency. Whether it's combating human trafficking or tweaking the tax code to provide help to Minnesota farmers, Klobuchar, 58, has made it her business to work across party lines — a trait even more valuable in this hyperbolic, tribal era.

She paired with Sen. Orrin Hatch, R-Utah, to get $1 billion to shore up security at the nation's schools, and with Sen. John Cornyn, R-Texas, on going after elder abuse. Even after Sen. Lindsey Graham, R-S.C., savaged Klobuchar, publicly demanding that she apologize to Judge Brett Kavanaugh after he aggressively challenged her questions, Klobuchar went on the Senate floor later that day to praise their joint efforts on a bill dealing with synthetic opioids. That speaks to self-control — a commodity in short supply among politicians these days — and the maturity to let small slights pass, also a trait seldom seen lately.

That Kavanaugh episode, it should be said, demonstrated nationally what Minnesotans already know about the senator: Underneath that genial exterior beats the heart of a cool-under-fire former prosecutor. When Klobuchar questioned Kavanaugh about his drinking, he came at her teeth bared, asking about her drinking and whether she suffered from alcoholic blackouts. Unrattled, Klobuchar calmly continued her line of questioning. When a cowed Kavanaugh later apologized, she accepted. Only later did she note that his behavior would have gotten him thrown out of most courtrooms. Her handling of that hot situation earned her national plaudits and was notable in a day dominated by grandstanding on all sides.

Always a diligent student of public policy, Klobuchar has gone deep on difficult issues such as health care. While others champion single-payer or a Medicare buy-in that would have to undergo substantial revisions to become workable, Klobuchar backs the less well-known Medicaid buy-in that would build on a coverage model that already includes both young and old and is built into state and county administrative systems. She has remained a committed champion of lowering prescription drug costs by allowing Medicare to negotiate with pharmaceutical giants.

In the face of a toothless Federal Election Commission, Klobuchar is leading efforts to bring some order and public disclosure to the Wild West of political digital ads, a number of which have been linked to Russian troll farms. A prodigious workhorse in Washington, Klobuchar also returns regularly to Minnesota, maintaining close ties with the culture and values of her home state.

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On the Republican side, state Rep. Jim Newberger is a hardworking and genial retired paramedic who served three terms as a state representative from Becker. While acknowledging that he's an underdog in the race, Newberger said he's mounted a challenge to Klobuchar to give Minnesotans on the right a voice in the U.S. Senate.

The Republican has cast his lot firmly with President Donald Trump, even making "Protect TRUMP" a signature campaign sign.

Newberger, 54, believes climate change is "driven by the sun," and that coal, a limited-supply fossil fuel, is the "energy source of the future." He opposes subsidies for renewable fuels because government "shouldn't pick winners and losers," seemingly oblivious to the billions of dollars the federal government has spent — and continues to spend — subsidizing oil, natural gas and coal.

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Given Klobuchar's stature, influence and rising national profile, we would like to see her expend some of her political capital to take a stronger leadership role among Democrats and help cast a new vision that could make that party more focused and viable. Pragmatic and effective, Klobuchar is perhaps uniquely positioned among Democrats nationally to bring a healthy dose of Midwestern sensibilities and values to a scene too often dominated by the hot rhetoric and flashy personalities of those who value headlines over results.

Minnesota Green Party candidate Paula M. Overby and Legal Marijuana Now candidate Dennis Schuller are also on the ballot.