> It's weird that the EU has a monetary union, but so much difference in corporate income tax rates.

That's because it's a monetary union, not a fiscal union.

> Great that IE is 12%, but this "competition" is BS in the sense that they needed the higher-tax countries to bail them out just a few years ago:

That's based on a severe misconception. The Irish headline rate is 12.5%, but the effective rate doesn't differ much from that. Meanwhile, you have countries like France with a much higher headline rate, but an effective rate much lower than the Irish one.

So no. Ireland was not bailed out by higher tax countries. Moreover, our corporate tax rate had nothing to the financial crises, whose roots in Ireland can ultimately be traced back to the ECB keeping interest rates artificially low to help with German reunification.