Tick, tick, tick. That’s what I say after I’ve been hiking in the woods and I’m picking the bugs off, but in this case it’s the sound of the presidential campaigns counting every minute left in the race. Here are my three things to watch — second by second — this week in politics.  

1. NUMBER CRUNCHING TIME: The post-convention bounce in the polls was more impressive for Hillary Clinton than for Donald Trump, but it’s all fading now. She still has a lead but Pew last week put it around a mere four points. You can bet both campaigns will hawk-eye any new numbers this week, and scrutinize the details. Keep watch on the state polls in the battlegrounds — places like Iowa, Ohio, Pennsylvania, Virginia, North Carolina and Florida. Trump needs some good news on those fronts or closing the gap nationally won’t make much difference.

2. TIME FOR A COMMERCIAL: Team Trump was shaken up like a martini last week, now let’s see the results. With some new hard hitters at the top, the campaign is finally putting commercials up against Clinton, who has been pounding the New York billionaire with tough ads for weeks. Don’t expect to see them if you are outside those battleground states I mentioned, but stay tuned: I’d bet my house pretty soon we’ll see another big Trump event to fire up his followers and scoop up more of that free media coverage that has served him so well.

3. TROUBLED TIMES FOR OBAMACARE?: Insurance giant Aetna is significantly cutting back on its participation in Obamacare. Other big insurers are too. Expert analysts say the program is not in a “death spiral” as some Republicans have predicted, but the program is in some trouble and it comes at a terrible time for Clinton. She faces a choice: Keep talking it up as a success or back away from it fast? Either way, watch for GOPers to step up their criticism tying her hard to the program.

(CNN’s Tom Foreman is the author of “My Year of Running Dangerously”)