You know, that "defense" has long since become offensive. At first it was denied that there was any fraud at all or that there COULD have been any. Then it was adjusted into the claim that there was no "evidence" of fraud, then no "significant" amount of fraud, and now people on that side just say whatever occurs to them, so long as it's some sort of denial.
But there is a mountain of evidence of fraud and sworn testimony of eyewitnesses, videos, government records, and so forth. While some of it may not hold up to scrutiny, it is nonsense to use (and mean it) any of these defenses.
What is reasonable is to say we don't know if the election outcome would have been different were it not for all of this, but it's the Democrats who have done everything in their power to prevent the investigation that would have put the issue to rest for good. That doesn't speak very well for their private confidence that there wasn't enough fraud to have mattered.