Transcript for First lady Melania Trump unveils official policy platform: 'Be Best'

Two major headlines involving the white house tonight. First lady Melania trump outlining her new initiative, and then, the president joining her, signing a proclamation to mark the day. The president also fighting back tonight, after his attorney, Rudy Giuliani, said he could not promise that the president would not plead the fifth, instead of sitting down with Robert Mueller. Here's ABC's senior white house correspondent Cecilia Vega tonight. Reporter: The first lady alone today as she walked into the rose garden to unveil her official policy platform. Her focus, helping children, in part, by combatting cyber bullying. A campaign called "Be best." Let us teach our children the difference between right and wrong. And encourage them to be best in their individual path in life. Reporter: As she emplored people to be kind, her husband, right there in the front row. Later joining her on stage with a kiss. A show of affection with their marriage under fierce scrutiny amid mounting questions about hush money paid to porn star stormy Daniels just 11 days before the election. And now, the president's attorney telling George Stephanopoulos it's possible other women were paid off, too, by president trump's long-time fixer and personal lawyer. Did Michael Cohen make payments to other women for the president? I have no kge of that but I -- I would think if it was necessary, yes. Reporter: Today, we pressed the white house for details. Is that possible, are there other women out there who received money from the president to stay quiet? I'm not aware of any other activity, but I would refer you to Rudy Giuliani to respond to any of those questions. Reporter: But you've been in his circle for a long time now, you were on the campaign. Is that anything that came across your desk? Again, I'm not aware of anything like that. Reporter: Rudy Giuliani says he still doesn't have all the facts, and he did little to clear up one big question, whether the president was lying last month on air force once one when he said he knew nothing about that payment to Daniels. Did you know about the $130,000 payment to stormy Daniels? No, no. Reporter: Giuliani's focus? Special council Robert Mueller, the prospect of a presidential interview now seeming increasingly dim. I'm going to walk him into a prosecution for perjury like Martha Stewart did? Reporter: Despite president trump's insistance on the campaign trail that only guilty people plead the fifth -- You see, the mob takes the fifth. If you're innocent, why are you taking the fifth amendment? Reporter: -- Giuliani says the fifth is on the table for the president. Are you confident the president will not take the fifth in this case? How can I ever be confident of that? Reporter: That, is, if he decides to come mril at all. But what happens if Robert Mueller subpoenas the president? Will you comply? Well, we don't have to. He's the president of the united States. Cecilia Vega is live at the white house tonight. And president trump tweeting about Robert Mueller today, but also about the Iran nuclear deal. The president promising a big announcement tomorrow? Reporter: 2:00 P.M. At the white house tomorrow, David. This is a deal he promised to tear up. European allies have been on a mission to convince him to stay in this deal. You'll remember, French president Emmanuel macron was here at the white house trying to convince president trump in person. The Brits made a last ditch effort, sending someone onto fox News, hoping president trump might hear their case. One European diplomat tells us tonight, it seems pretty evidence president trump will exit this deal. We'll be watching with you tomorrow at 2:00 P.M., Cecilia.

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