The Langer case involved Mamzerius which is one of the hardest things in the torah to defend , If not the hardest to a non or semi-religous population.
Ivanka Trump doesnt involve Mamzerius
Its one of those things I thankfully was not there at the time to have to make a decision. As stated in at least 2 cases above and others Ive heard about Sometimes there are outside pressures when it comes to Gerius,
One that I heard of involved a woman in Germany who was married to a Cohen. She was a little mentally unstable and they had a baby and it died. She then decided the reason the baby died was because she wasnt jewish and then demanded to be converted to Judaism. She petitioned the German government to be converted to Judaism and they put pressure on the Rabbis of Germany to convert her. It was not a Shalia Id want to be asked. A mentally unstable person who lost a baby already married to a Cohen. Thankfully I wasnt asked