Once Christianity was vibrant and powerful enough to stop it But certainly no longer.
And what else could stop it?
Tanks and guns against ideas? That is no match. Ideas will win every time. People willing to blow themselves up along with as many Jews and Christians as possible simply can not be stopped by all the guns and bullets in the world. The more you throw at them the happier they are.
Personally I see Christianity not just as lukewarm, but also mistaken on a few fronts.
My own approach is that of the Gra and Reb Israel Salanter and Rav Elezar Menachem Min Shach on three fronts. Learning Torah, Ethics, Learning Torah in depth.
This more or less goes along with Reb Shmuel Berenbaum's (the Rosh Yeshiva of the Mir in New York) idea when he was confronted with life problems that people asked him about. His answer was "Learn Torah" but never at the expense of doing kindness in places that were needed.
That was his idea of the one and only solution to all individual and all of mankind's problems. Thus it is my suggestion for people to acept on themselves to learn Torah every day for at least one hour (that is to accept bli neder [with no oath]).
That is for one hour to learn either the Written Law (Old Testament) or the Oral Law [The Two Talmuds] in such a way as to finish them at least once. Girls that are not required to learn Torah should be committed to marry guys that learn Torah.
[What counts as Torah? Books of חז''ל the sages of the Talmud which includes the midrashei halacha and midrashei agada. Rishonim mediaeval sages. Musar. Plus a few achronim like the Maharsha and Rav Shach.] [To the Rambam, Physics and Metaphysics are included in the Oral Law, but in my view that would mean to learn the Talmud in one hour per day session, and in another session learn Physics or Metaphysics. The Rambam obviously meant Plato, Aristotle Plotinus, but I would add Kant and Hegel