The video screen outside went dark, silencing the antigovernment chants from Kiev and, at least on the surface, restoring Dnepropetrovsk as a bastion of calm support for Ukraine’s embattled president, Viktor F. Yanukovych.

Caught in a titanic tug of war for influence between Russia and the West, Ukraine is also being tugged in opposite directions by the forces facing off at the Passage mall in Dnepropetrovsk. In an economy dominated by a relative few wielding enormous wealth, the outcome of the struggle could well hinge on how many other businesspeople make the same switch as Mr. Korban and Mr. Filatov and join the street in rejecting Mr. Yanukovych’s tilt toward Russia.

The defection of two provincial businessmen — motivated as much by resentment of the strong-arm tactics of rivals in league with the government as by lofty ideals — will not tip the balance of power in Kiev or even here in this city of more than a million people, its economy dominated by huge Soviet-era factories like Yuzhmash, a rocket maker still owned by the state.

But it underscores how a protest movement that the government dismisses as the work of nationalist extremists from the country’s west has reached into Mr. Yanukovych’s political power base in the east and is even eroding the loyalties of those who have thrived under him.

And it shows how, for all their differences, the disaffected moguls and the protesters are driven by a deep frustration with what they see as the country’s lawless law-enforcement system and ubiquitous corruption. Both camps call for not just democracy but for a more “normal,” European-style government with transparent institutions, secure property rights and an impartial justice system.