Republican presidential front-runner Donald Trump said "the dumbest people" occupying positions of power have led the US astray. The comments came during a campaign speech in Iowa on 15 January.

"We don't want to be the stupid people anymore. We're not going to be the stupid people anymore, because right now we're the stupid people. We have the dumbest people leading our nation. They're leading us, they are leading us into the worst positions," Trump said during a campaign appearance in Urbandale, Iowa.

Trump's comments came the day after he and top challenger Ted Cruz ended a longstanding truce in spectacular fashion on 14 January with bitter exchanges during, in what may have been Trump's strongest debate performance to date. The New York billionaire and the Texas senator appeared to have a split decision by the end of the night, a sign that for all the bluster, little took place that could derail Trump from his lead position as before voting begins in Iowa to pick the Republican presidential nominee on 1 February.

Projections that the debate would be a free-for-all were accurate. Beyond the Trump-Cruz theatrics, US Senator Marco Rubio of Florida turned in a pugnacious performance with attacks on Cruz and New Jersey Governor Chris Christie. Florida governor Jeb Bush presented himself as a voice of reason against Trump.

A Google snap poll showed viewers believed Trump, who in the most recent debates was at times less engaged, won the night with 37.3% to Cruz's 26.6% and Rubio's 12.1%.

A Reuters/Ipsos rolling national poll on 12 January showed Trump had 39% of the vote, Cruz 14.5%, Bush 10.6%, Carson 9.6%, while 6.7% favoured Rubio.