Barack Obama is one of the most talented politicians alive. He built his entire career around public speaking.
It was the speech at the Democratic National Convention in 2004 that catapulted him onto the national stage. His long shot bid for the presidency in 2008 was built around speeches, and so was his reelection campaign. Once in office, and when Congress was controlled by Republicans, he tried to advance policy by mobilizing public opinion trough speeches.
In an article for the Communication Intelligence Magazine, I discuss together with other experts the takeaways from the case of Obama. To a certain degree, public speaking can be learned. It has to be done by the candidate himself, however. This is not something that can be delegated.
You can read the article here.