A brand new poll from CNN, not known for favoring anything about Donald Trump or Republicans, is shocking the Biden campaign.  It shows Biden's national lead among registered voters shrinking to 4%, down from 14% in early June.  Keep in mind that polling registered voters generally favors Democrats, while polling likely voters typically adds support to Republicans.

Another key point to keep in mind is that national vote totals mean nothing.  Democrats pile up huge majorities in blue states that go to waste in terms of Electoral College voting.  All that matters are the state-by-state elections.  And as CNN's summary of the poll concedes:

Across 15 battleground states, the survey finds Biden has the backing of 49% of registered voters, while Trump lands at 48%.

The pool of battleground states in this poll includes more that Trump carried in 2016 (10) than were won by Hillary Clinton (5), reflecting the reality that the President's campaign is more on defense than offense across the states. Taken together, though, they represent a more Republican-leaning playing field than the nation as a whole.

CNN also flags a huge shift among male voters, from an even split to a 16-point margin for Trump:

The movement in the poll among voters nationwide since June is concentrated among men (they split about evenly in June, but now 56% back Trump, 40% Biden), those between the ages of 35 and 64 (they tilt toward Trump now, but were Biden-leaning in June) and independents (in June, Biden held a 52% to 41% lead, but now it's a near even 46% Biden to 45% Trump divide).

Polling expert Richard Baehr speculates that CNN has adjusted its polling assumptions:

CNN's June poll with a 14% margin for Biden seemed too high, so they may have  over adjusted this time.  Polling involves a secret sauce — weighting various groups, and parts of country to get an appropriate mix. Nobody knows what any pollster does in this regard.  

Richard also notes:

Betting odds favoring Biden have dropped from 60-39 to 56-42.

I am increasingly optimistic.  The media have been presenting the Democrats' case for the entirety of Trump's presidency.  Trump is only now entering Act Three of the narrative that should culminate in victory, and a lot of surprises, including probable indictments, lie ahead.