How have the European politicians solved the problem of being able to get elected in order to implement policies that may make them unelectable? Are they just (even) better at lying about what they plan to do than are American politicians?

There are occasional flashes of prudence and spine, and yes, that is sometimes probably accomplished by deception: sell optimism, govern with reality. That's not such a bad thing I guess, if the mismatch is in the direction of good governance.

But on the whole I wouldn't hold them up as glowing beacons of skill and prudence, just adequate.

The UK in particular has suffered from what I call "performative governance": doing not the things which have to be done or which could possibly work, but something that can be pointed to as doing something about some issue. One example might be a recently introduced huge regulatory system to ensure that no-one without a permanent residence permit can rent a flat, on the theory that this will halt illegal immigration since they won't have any place to live.

A couple of countries simply aren't good at figuring out how to be electable and at the same time staying within the real world range of fiscal possibilities. Maybe they don't lie enough?

All that could constitute muddling through, which has largely worked for a long time. The bigger threat, of course, is the fresh crop of apprentice dictators following the classical playbook: invent an enemy (one internal, one external), gut the courts, control the press and TV, divide and jail the opposition, position yourself as the one true patriot who can fix things, then remove term limits. Seems to be a lot of that going around.

Jim