Tantra is a means, a way of reconciling everything.  It's neither here nor there, forward nor backward.  It's a state of awareness.

The winds of eternity blow, and in tantra, we have complete faith in the winds of eternity. The key to tantra yoga is to feel that you are not the doer. That you cannot possibly act. That anything that you choose, you didn't really choose, eternity chose for you. All that you have to do in existence, in live, is accept.  In bhakti yoga, there is a sense of "I'm loving god, I'm serving god."  In karma yoga, there is a sense of "I'm working for the welfare of others, I see god in everyone and I work for them." In mysticism, there is a sense of "I am impeccable, I am bringing forth the powers of eternity and working with them." In jnana yoga, there is a sense of non-existence of the self, "I don't exist, nothing exists, the relative world doesn't exist, all that is is nirvana."
 
In tantra, there is a sense of surrender. True, all of the yogas do lead to this sense. The highest aspect of all the yogas culminate in a sense of surrender to eternity, "Let thy will be done." But tantra is really that way from the beginning.  What can I do, I'm a poor, puny human being. How can I possibly rise above the samsara, the illusion of birth and death, of pleasure and pain.  Here I am stuck in the middle of the relative world in a traffic jam and there's nothing good on the radio. And I'm dying every day. My body's aging. My life didn't turn out the way that I thought it would. When I try to feel and communicate, there's little feeling and even less communication.
 
At that point, it is necessary to break out of the framework with which we view experience. So then in tantra, we come to feel that that very frustration is the means that eternity is using to break us out of our conditioning.
 
If, for example, you feel that you shouldn't eat an ice cream cone.  I don't know why you'd feel that way, but if you feel that way and you feel that it is a very 'unspiritual' thing to do, and yet you're drawn to the ice cream cone and you find yourself eating one, in spite of your intent. If you follow any of the other paths, you'll be miserable. You'll try and accept it as an experience that god is having through you, but still you'll know you've failed.
 
In tantra, you'll order a hot fudge sundae, and in every bite of that hot fudge sundae, you'll see and feel god vibrating. The path of tantra doesn't mean that you'll go out every day and seek out hot fudge sundaes, but whatever comes your way, you will accept as being normal, natural and perfect.  There are no rules for you to break. Since everything is god and everything contains god, you see god in everything. Everything is a step towards liberation.
 
 - Tantra and the Left-Handed Path