I have an older Briggs and Stratton mower of the type you can get at Home Depot.
I think something in the safety mechanism broke. The safety mechanism is a bail on the mower handle that must be depressed to allow the engine to start. The safety cable (called the "stop cable") and its latch are ok, but I think that whatever they connect to inside of the engine compartment broke.
Is this a repair that is easily possible, or will it be a can of worms to open up the mower?