So, there has been a steady, if marginal, drift downward in Mr. Biden’s lead, at least in the last 30 days. Time alone will tell if that will continue.

But the results taken as a whole should prompt some concern in the Biden camp. One way of looking at the race is that Mr. Biden has held onto a comfortable margin for a long time. Here’s another way: Despite everything that has happened in the last six months, Mr. Biden has been unable to put away the president.

Team Biden has been playing prevent defense for five months now, hiding the candidate and hoping he can hold off Mr. Trump for just another 80 days. The problem with that is by allowing the president to hang around, Mr. Biden has placed himself in a position in which the slightest mistake or hiccup on his part, or the slightest bit of good news for the president — a vaccine? unexpected economic good news? — may touch off a surge, even a modest one, for the president that may be dispositive.

Mr. Trump has taken the hardest punches that Mr. Biden and his media allies can throw at him and is still standing. It is still a fight.