Yes. Mara encourages us to not believe in our potential to overcome Mara. Mara wants to be in control, doesn't want you to end your ignorance. Most of us know Mara, don't we? That is the Mara that keeps on saying, "You don't have the potential. Why even try?" That is why we need to reflect on confidence inspiring objects of meditation like the Buddha and the Sangha. To know that it is possible. However, if one cannot resist desire, yes, of course, Mara is in control at that time.
Mara wants you to stay ignorant and Mara wants to remain in power. Mara is within ourselves, but as I was explaining to someone, Mara can be a friend, too. The wrong views in other people, the external Maras can teach us. Mara is Wrong View and Mara can manifest as many things.