Francois Hollande won election to the French presidency by promising that more government spending would lead to quick economic growth. He sharply criticized the “austerity”—i.e., sudden spending cuts—proposed by his opponent.

A few months later, Hollande has come full circle. In addition to a tax increase that has wealthy French taxpayers heading for the borders, he is now offering cuts in government spending and shrinking the entitlements his constituents wanted him to expand.

But Hollande cannot deliver on his promises. Keynesian-style stimulus has already failed in France: Despite massive deficit spending in 2012, economic growth has stalled. Now, Hollande is forced to pursue austerity by cutting spending and raising taxes.

Hollande offered voters a choice between spending and austerity. But the real choice was taken years ago between prudence then and austerity now. Having been imprudent in the past, France must be austere now in order to avoid a debt crisis. After all, Hollande is entitled to his own politics, but he’s not entitled to his own mathematics.