I've noticed in recent years that politicians will claim to have no recollection of their own words, actions or having known about facts that would implicate them in any wrongdoing. This happens when questioned by reporters, but also in parliament sessions and even investigations by committees, where the politician can be questioned under oath.
This convenient amnesia seems the default now in Dutch politics, but the US and UK also see a lot of this happening. It makes sense for the politician because in the digital age it's very hard to prevent evidence from leaking out, so a hard denial can come back to bite you. But it is my opinion that it is very damaging to the country's citizens if their politicians can't be held to account for their words and actions.
How would it be possible to limit this "defense" and hold politicians somewhat accountable for their actions. Examples of actual measures taken in other countries would be best, legal standards from (civil) law that could be adapted to political procedures would be second and alternatives (competency rules that disqualify amnesiacs) last.
Specifically not wanted are solutions that depend on per-case majority votes (like a vote of no confidence).