Depend how you define “ally”. Since Germany is in NATO, military alliance is out of the question, but up to last year the prospect of serious economical alliance was real. And that would undermine NATO itself by increasing Germany control over EU and eroding USA influence.

Or at least everyone thought this is happening, but it turned out that the german elites with Merkel on the lead were and are in fact american compradors who only opportunistically wriggled under in the USA boot, because what i just wrote paragraph above would be in best interest of Germany, yet what happened is the opposite.

I doubt they can now turn around, but if the current government was toppled by protest and something less compradory emerged (idk if that’s possible, extent of US inflitration of german political class could be much worse than i suspect, i was terribly wrong about it last year), they could again ride both sides which would be more beneficial to both Germany and Russia. Eventually it will happen anyway, but as everything moving in Europe, it can only move either with NATO consent or when NATO wane. So it’s all again come to the USA being the pillar of global imperialism, just as Che Guevara said 70 years ago.