BETTENDORF, Iowa (AP) — Republican presidential candidate Jeb Bush told an audience of Iowa party faithful Tuesday that a conservative will win the White House if the GOP convinces middle-class Americans it can knock down barriers to economic growth.

Bush's upbeat message to GOP activists in eastern Iowa matched the tone of a new campaign video also released Tuesday.

"A conservative will win when we go campaign and encourage and give people a sense that their lives can be better," Bush said at the Scott County Republican Party's annual Ronald Reagan dinner. "This should be the greatest time to be alive in this world."

In the new video, Bush says, "The source of optimism I have is because I know the American people and its ability to innovate, to create."

Bush was returning to what he has said would be joyful campaigning after pivoting late in the summer to answer attacks from billionaire GOP rival Donald Trump, whose lead in early states such as Iowa and New Hampshire has dipped in recent Republican polls.

Bush also echoed his closing remarks in the second Republican debate, held last month in Simi Valley, California, where he characterized the plight of specific Americans he hoped his agenda could inspire.

"It's about the single mom who has a kid in a languished, failing public school," he said. "I have my energy and passion thinking about them."

Bush was beginning a three-day visit to Iowa, home of the lead-off caucuses, and planned to cover an eastern swath of the state. The area's Republicans tend to be moderate — Mitt Romney won the region during his 2008 and 2012 campaigns.

Bush focused primarily on economic and government reform during his 25-minute speech, and did not touch on the hot-button social issues important to the social conservatives more prominent in rural northwest Iowa.