We barely have technology within our lifetimes to get one man to Mars on a suicide mission. Even if you pored all the resources of all mankind's wars it would barely be better and that's just to the nearest planet
We have the technology within our lifetimes to send multiple people to Mars on an extended scientific research mission and return them safely to Earth. What we lack is the will to expend our resources on such an endeavor.
That said, interstellar travel is orders of magnitude more difficult.