Yes, ALL the votes need to be verified. It's not a question of which party the votes went for. The problem is, you simply cannot have an unverifiable way of voting (by machine, I mean) if you want to avoid fraudulent election results.

Political parties CHEAT! Whenever and wherever they can...as long as they think they can get away with it. They always have, they always will. To put votes into a machine that cannot be audited simply means this: someone somewhere will bribe someone else and arrange to have some of those machines or even all of them deliver the victory to that someone's candidate. They will do it, depend on it.

The only way you can prevent that is with paper ballots that are verifiable.

As a matter of fact, each citizen who votes in an election should be able to take away a paper copy...in effect a receipt...OF his or her written vote! This could be done with utter simplicity, by providing a pressure-sensitive second sheet on the ballot. Citizen keeps second sheet and leaves with it after voting. And those could be the final evidence for a recount, beyond anyone's ability to tamper with.

I bet that idea would give corrupt party organizers fits. I can just hear them..."Oh, no, that would be...um...too expensive!"