Republican frontrunner Donald Trump touted his growing lead in the polls at an election rally in Iowa on 25 August, and launched a scathing critique of politics in Washington, calling most politicians "impotent".

Speaking to a large crowd in Dubuque, Trump cited a Gravis poll released Tuesday that puts him nearly thirty points ahead of his nearest rival nationally. "The Gravis national poll just came out - 40.1 percent, that's national. 40.1 percent. I want the election tomorrow."

A Reuters/Ipsos poll released on 25 August also showed that Republican Jeb Bush's support is slipping in the race for the party's presidential nomination, and that Trump has opened a 20-point lead over his closest rivals. Trump has attacked his rivals for being career politicians in the pocket of special interests, and today continued to pillory Washington politicians as "impotent".

"I don't know, there's something about Washington. They look at these beautiful buildings, these beautiful halls and all of a sudden they become impotent. Is that an appropriate word? I think so. They become, just, it doesn't work. Put those two together. Something happens to them. And all of a sudden they're not fighters. I think they're so impressed, they show they're wives, look where I'm working, I'm working in congress. Of course I've got to vote for Obamacare, isn't it wonderful? Look what I'm doing. But they got elected to knock it out. What happened to these people? What happened?", he said.

The Reuters/Ipsos poll shows that Trump's support has remained largely unchanged over the last week at about 30 percent, well ahead of the 17-strong pack seeking to represent the Republican Party in the November 2016 presidential election.