As a young physicist during perestroika, he organized protests against the construction of nuclear power plants in the wake of the Chernobyl disaster.
He was among the first generation of Russian reformers elected to the Soviet legislature, where he pushed for democratic change.
When he was just in his 30s, he was a popular and path-breaking governor of his native Nizhny Novgorod in the heady days following the Soviet collapse.
As deputy prime minister, he struggled to reform Russia's corrupt and bloated energy sector, and was seen by many as a potential president.
And when Vladimir Putin ended Russia's democratic experiment, he became an uncompromising opposition leader who refused to be co-opted -- and who persevered, even when it appeared that nobody was listening.
And a year ago this weekend, on a drizzly Friday night in Moscow, Boris Yefimovich Nemtsov became a martyr.
In many ways, Nemtsov represents the path not taken.
He was one of the finest representatives of what I like to call The Other Russia.
The one that inspires, the one that belies the stereotypes, the one that offers a glimpse of the just, confident, and constructive country -- at peace with itself, its neighbors, and the world -- that Russia could be.
We miss you, Boris Yefimovich. Your country, and those of us who care about it, need your vision now more than ever.