They won't achieve anything without popular support (UNLESS)
Unless they win/have/get popular support, they won't achieve anything.
I'm in favour of the idea so long as it's not too expensive. (PROVIDED / too much money)
I'm in favour of the idea, provided it does not cost / they do not spend... too much money
It doesn't matter if you dn't like it. That doesn't stop it happening, does it! (WHETHER/ It's always going to happen)
It's always going to happen, whether you like it or not!