2008 Mazda Tribute...You have to turn key all the way back as far as it will go. Sometimes you have to repeat several times before it will start. Starter is good,battery is good. If you turn it really hard as far as it goes it will start up!

 

There seems to be something wrong with the starter switch. The key unlocks the switch and the various positions activate destinct circuits. Turning the key all the way should activate a relay which closes the starter circuit.

So either that switch or the relay are not up to snug. you could swap out the relay to see if it fixes the situation before you tear out the ignition switch/lock.