KIEV, Ukraine — Few politicians in the world have had to undergo the same experience twice in their career and in different countries. Yet this is exactly what happened to me in Ukraine and Georgia.

I was the president of Georgia for nine years, during which it went from a kleptocracy and failed state to a country that won international recognition for tackling corruption and became one of the easiest places in Europe to conduct business. Named the world’s top reformer by the World Bank in 2006, Georgia became a flagship among the countries of the former Soviet bloc.

After my second presidential term in 2013, I left to pursue academic work in the United States for a time, and then returned to Ukraine — where, as a young man, I had spent several years at Kiev University. Responding to calls from my Ukrainian friends to help apply my experience in government, I arrived along with the wave of enthusiasm for reform that followed the Maidan revolution.

I offered to work in Odessa, the largest region of Ukraine. It was highly unusual for a former president of another state to serve as a governor in a different country, but the very fate of Ukrainian statehood was at stake in Odessa. The province was not only riddled with local mafia groups infamous for their thuggishness, but it was also threatened by the conflict with Russian-backed separatists in the east. Odessa borders the breakaway region of Transnistria in Moldova, which is controlled by Moscow-backed separatists and Russian armed forces.