The winding roads to this town in northern Rwanda were lined with election posters for the man who has been president for decades: Paul Kagame.

Businesses were ordered shut and women swept the streets before the president’s convoy swooshed by, heading for a huge rally in a stadium bedecked with the governing party’s red, white and sky-blue colors. Tens of thousands of cheering people, largely mobilized by party operatives, greeted his arrival.

A day later, Mr. Kagame’s main challenger, Frank Habineza, arrived in the same town without a fanfare. His party’s colors — green, yellow and white — were absent from the now-busy streets. A few dozen people, many of them his own election workers, gathered under a tent by the street to listen to him. Security forces hovered nearby.

Two parallel Rwandas were on display on successive days in Byumba — a town of verdant, rolling valleys, 25 miles north of the capital, Kigali — showcasing how President Kagame is wielding the power of his decades-long incumbency in an election campaign in the Central African nation.

On Monday, more than nine million people will cast their ballots in a presidential and parliamentary election that analysts and rights groups say is a rubber-stamp vote with a foregone conclusion. Even though hundreds of candidates have registered to run for various seats, only Mr. Kagame’s face dots the landscapes of this hilly, landlocked nation of 14 million people.