Transcript for Trump plans full campaign schedule for midterms

nobody will believe you. Jon Karl, thanks very much. Let's bring in Matthew dowd. We have pretty competing narratives going into the final week before the midterms. You've got the focus on the shooting in Pittsburgh and potential pipe bombs last week and the president rising to change the focus to immigration. How do you think it will play out? I think it's a risky bet for the president in what he's doing in the course of this but the president has been known for risky bets that have paid off sometimes and sometimes not paid off, the problem, the number one issue among voters is health care and he knows and the GOP knows the Republicans are on the defensistic on health care. So the dominant issue is health care. He's doing something unusual in the final week before a midterm, a first midterm for a president when there's usually a redwrakz to the president. He has a full campaign schedule in the final seven days. Reporter: Yeah, and I think as I say it's a risky bet because he's now going to own the results of the midterms so whatever happens in the house, in the senate in the gubernatorial races and the other thing I think he has to worry about for all the motivation he's doing for his base, the question for every one voter he motivates from his base does he move two independent voters away from him and I think that's a risk he has because independent voters are not siding with the Republicans. What's the single most important thing you'll watch in the final week? I'm going -- as of now the president's job approval rating eating is 40% positive in the latest Gallup poll, 54% negative, which is the lowest historic number a president has gone into in modern times. I'm watching that and that differential is something like 18 points and 20 points among independent voters and independent voters will decide the election. Matt dowd, thanks very much.

This transcript has been automatically generated and may not be 100% accurate.