If you mean you pushed the small wire in towards the coil itself, then apparently there' damage on the inside and replacing it is the only sure way to fix it. Now if you mean pushing the wire connectors together, that's a different story.
Sometimes die completely, but normally they go to missing first or sometimes they miss only under heavy loads or acceleration. Personally, if you have to replace the coil, I'd go with something like Nology, Dyna or Accel. They're produce a hotter spark but to actually get improved starting, high speed running and fuel mileage, you must widen the plug gap as well. I'd be looking at at least .035" or preferably .040". If the coils don't have plug wires, you better look at 8mm wires with thick insulators because otherwise you'll get arcing through the older style thin rubber caps and insulators.
Andy pretty well said it, although I will make a few corrections to his explaination. To begin with, magnetism and electricity are interchangable, meaning one can be used to create the other. Ignition coils don't built up in voltage until triggered, but instead the primary winding (few windings of thicker wire) "saturates" with current, producing a magnetic field. When the points or ignition unit close the circuit, the current flows to the ground, collapsing the magnetic field in the primary winding. When that happens, current is is induced in the secondary winding (more windings of smaller wire). The greater number of windings multiplys the voltage from approximately 12-14V to 18,000-35,000V.
What he said about the coils not having time to build a hot spark at high rpms isn't true with most modern electronic ignitions. The amount of time the primary winding has to ssaturate is called dwell. Modern units increase the dwell time at higher rpms, giving the coil more time to saturate and thus deliver a hot spark.