Well we know that’s flat out not true.
We know for a fact AT LEAST two members of the Trump campaign colluded or attempted to collude with Russia.
Manafort, the chairman of the Trump campaign, was passing internal polling data to the Russians. There is no other word for that except collusion.
Trump Jr., not to mention the others involved, agreed to meet what the believed was a Russian government attorney with dirt on Hillary Clinton as part of Russia’s attempts to help get DJT elected. How is that anything other than collusion?
Not to mention Roger Stone and his Wikileaks shenanigans. Or Flynn and the sanction phone calls.
And that’s likely just the very very tip of the iceberg.
Maybe he could say they have no concrete evidence showing Trump himself colluded with Russia, but it is an absolute fact at this point that several members of his team did.