Politicians who never made it to the big time despite high profile starts

Justin McAleese. Tried a run in Dublin Rathdown with FF but never gained any traction.

Royston Brady. Thought he was going to be the next Taoiseach

Sean Haughey. A TD for 25 of the last 30 years. Genuinely never hear of the guy other than when the election posters go up. Probably someone who was elected on the same family name that has also held him back from higher things.

Think he was Junior Minister for School Buses once.

As well as being the youngest TD elected at 21.

He left politics of his own accord

This was going to be my reply. I remember visiting Dublin in 2004 and his face was on every lamppost as he was running for Europe at the time. There was a few different poster variations but all in the same style - they had a big picture of him and then some nonsense, meaningless, word on top like "Energy", "Passion", "Drive". This was the Celtic Tiger era so pretentious guff was all over the place but this was another level. He was the Lord Mayor of Dublin at the time and it seemed like he was going to be the next big star of FF. His campaign ended up flaming out though and according to wikipedia he lives in the USA now.

Kate O'Connell: She was tasked with taking out Lucinda Creighton in 2016 and she did just that. Got plenty of media appearances as a young, attractive pharmacist with good communication skills. The sky looked to be the limit for her. Things went wrong pretty quickly though. She backed the wrong horse in the 2017 leadership challenge, said some stupid things and made a mortal enemy of Leo Varadkar. Losing her seat in 2020 was bad but getting passed over for a Seanad nomination and then, worst of all, being completely overlooked for the nomination to run in last year's by-election.

She claims that she hasn't ruled out a return to politics but she's burned a lot of bridges in FG so it's difficult to see a path ahead for her especially while Varadkar is still leader of the party.

It was the European elections she was running in.

Nope. It was the 2019 European elections. This was the year after Casey had run for President. Both herself and Casey were running in the Midlands-North-West constituency. She was the Green Party candidate and criticised Casey in the televised debate and was seen as one of the star performers on that night. That was her debut as it were.

As a campaign slogan, it was, if nothing else, unique, in a sea of "working hard for you" type blandness.

I’m open to correction but think he only failed to be elected as a TD once in 2011 when FF were wiped out.

he tried in 87 and 89 in dail elections while he was in the seanad and failed both times.