"No political party caters to your interests, and then you vote. It will never ever work that way in a million years.
You vote, and then that party caters to your interests."
I suspect I'm misinterpreting you, but I'm struggling to understand this.
This reads at first glance like you're saying the following:
"A party will put forwards policies that you don't agree with, and do not cater to your interests. However, you should still vote for them.
"Once you have voted for them, they will then abandon those policies, and instead pursue policies that (instead of the ones you ones you condoned and endorsed with your vote), cater to your interests."
That doesn't seem accurate to me, to be totally up-front with you.