If there is a deceit. it is that Trump is powerless: he most certainly still has power
Democrats wish to indulge in the power of positive thinking and diminish Trump's persona as unbeatable.
There is a great deal of wishful thinking in this claim. though there is truth to it.
This is a political claim made by the opposing party.
Not many folks will unconditionally believe a claim like this anyhow. especially made in the middle of a contentious political season.
To weaken the idea that Trump is unbeatable and that his power is undiminished
In politics perception is everything. This lie/truth is designed to damage Trump's image as unbeatable.
Though his enemies would like it to be 100% true, it is not. He still has considerable influence.
As a component of a Democratic political strategy. and within that context. the lie is acceptable.
This is somewhat true, though Trump's influence is still formidable
His influence has been fading a bit. but is still strong enough to be a factor. Maybe he is just waiting until the next elections