Does alliance with disbelievers expel you from Islam?

I have a question about these ayat (5:51 and 3:28 ): > O you who have believed, do not take the Jews and the Christians as > allies. They are [in fact] allies of one another. And whoever is an > ally to them among you - **then indeed, he is [one] of them**. Indeed, > Allah guides not the wrongdoing people. > > Let not believers take disbelievers as allies rather than believers. > And whoever [of you] **does that has nothing with Allah**, except when > taking precaution against them in prudence. And Allah warns you of > Himself, and to Allah is the [final] destination. > Do they mean that whoever does this *literally* becomes a disbeliever and is expunged from Islam? Or does it mean that this action is very grievous but not real kufr?