Friedrich Merz is about to discover whether his plan to reboot Germany will succeed.

The chancellor¡¯s massive infrastructure stimulus is starting to feed into Europe¡¯s biggest economy, with €24 billion ($28.6 billion) already disbursed by the start of this year and hundreds of billions more on the way. A ramp-up in defense spending should provide further impetus.

The critical question for Merz and Finance Minister Lars Klingbeil is still to be answered: When will it generate results?