If the ideological root of your governance cannot withstand a newer competing ideology without its compromise, then at face value your ideological system is 1) flawed, 2) deserves to die, and 3) will inevitably die; with haste.
I do not believe this to be true and representative democracy managed to survive the larger half of a century with opposition from fascism, socialism, communism, autocracy, modern dictatorship and Orwellian totalitarianism. I think this trend will continue but it seems that you do not.
Keep in mind that a full third of the English language comes from German. In the 20s & early 30s, one of the largest and most financially/socially successful groups of immigrants in the US & UK were German. Germany and Fascism were politically very popular here and openly supported until (and on the US side, part-way through) WWII. Even under those circumstances, it was politically untenable. This is even more true now.