If you're falling from the sky your death is inevitable its not much of an option to choose it. However it is definitely an option to pull and release your parachute, right? I think in similar terms scripture paints a picture of humanity without Christ as already being condemned and so salvation is an ultimatum of circumstance as opposed to simply choice. We are condemned without Christ with a definite end of condemnation, yet salvation is available to those that would repent. Hence, God draws and man responds thereby crediting God with the glory.
For those worried of someone boasting that they believed, keep in mind that it is impossible to please God without faith. Why would scripture share this information with us if faith itself wasn't something that came from us but was cultivated by God? For God to take pleasure and pride in His creation having faith, a faith that He himself supposedly gifted would be illogical. Rather, God brings conviction to the world of sin, righteousness, and judgement and through such conviction (and convincing, if you will) man responds to the facts. Is God a liar? No, so repent.