And this week, the democratic national convention, and as we come on the air tonight, not long from now on that stage. Thfirst lady michelle obama will enter the arena do give a speech to millions of... See More
And this week, the democratic national convention, and as we come on the air tonight, not long from now on that stage. Thfirst lady michelle obama will enter the arena do give a speech to millions of americans about her husband and the pressure is on. Because a brand-new abc news/"washington post" poll shows the president has been sliding among registered women voters, some of his strongest, most steadfast supporters. Take a look at the poll. In april, 57% of the women said they approved the president. Today, just 46%. And for the first time, more women slightly disapprove of the president than approve. That is a new low. So what is going on? Is this real and what does mrs. Obama have to do tonight, it's "your voice your vote." And our political team has out in force all day. Let's lead off again with abc's ja jake tapper down on the convention floor. Good evening, those are bad poll numbers for president obama with crucial votes, all eyes on first lady michelle obama as she comes to the podium to try to shore up that pivotal group. Michelle obama came to the podium to help voters connect to her husband while the president can seem cool andal lo aloofs, the belief it is one of his greatest Millions of americans who know that barack will fight for people like them. And barack will free finally the change that we need. Reporter: So tonight, with the president having a record about which many voters feel ambivalent. The first lady has a simple but important task, to testify for his empathy. I'm going to remind people about the values that drive my husband to do what he's done and you what he's going to do for the next four years. She hopes they will believe in his motivation. She'll describe how his mother's health care struggles pushed him to pass a health care law. Whatever I say here today, it's going to be at best a good second to the speech will you hear tonight. Reporter: Norfolk, virginia, this afternoon, the president said he's looking forward to his wife's speech. I'm going to be home and I'm going to be watching it with our girls. And I'm going to try not to let them see their daddy cry. Because when michelle starts talking, I -- I start getting all misty. Reporter: His motivations may be an easier focus than an economy that is still sputtering, and a national debt that this afternoon is $16 trillion. In the first year of his presidency, oprah winfrey asked the president to grade himself. B-plus. Reporter: More than 3 1/2 years into his presidency, he gave this answer. I would say incomplete. President's obama's answer, of course, not meeting with approval from republicans who says it's gets an "f." Paul ryan said this evening that president obama's self-grade of incomplete speaks for itself.
This transcript has been automatically generated and may not be 100% accurate.