Marco Rubio is Iowa-bound for fundraiser for Joni Ernst

Potential presidential candidate Marco Rubio will be in Iowa on Saturday as the special guest at a private fundraiser for Republican U.S. Senate candidate Joni Ernst.

GOP fundraiser Bruce Rastetter confirmed to the Register on Thursday that Rubio, a Republican U.S. senator from Florida, accepted his invitation to come to both the fundraiser for Ernst and his annual summer party Saturday.

The two invitation-only events will take place at Rastetter's property in rural Hardin County, about an hour north of Des Moines.

Rubio, who endorsed Ernst during the five-way GOP primary for Iowa's open U.S. Senate seat and put significant resources behind her campaign, booked the Iowa trip months ago. This week, a second VIP political figure, Texas U.S. Sen. Ted Cruz, made a last-minute RSVP and will attend both events as well. Cruz didn't offer support in any of Iowa's Republican primaries this year.

This will be Rubio's third trip to Iowa since Mitt Romney lost the 2012 presidential election. He was the featured guest at the fundraiser for Gov. Terry Branstad's 66th birthday on Nov. 17, 2012, and he flew in on the eve of the June 4 primary this year to stump for Ernst.

A passel of possible presidential aspirants will be in Iowa in coming days: Kentucky U.S. Sen. Rand Paul starts a three-day test-the-waters trip Monday; Louisiana Gov. Bobby Jindal and former Arkansas Gov. Mike Huckabee will speak next Friday and Saturday to gatherings of evangelical Christians; Texas Gov. Rick Perry launches his four-day tour next Saturday; former U.S. Sen. Rick Santorum of Pennsylvania will be here next Friday and Saturday; and Cruz will be back next weekend, too.

Santorum endorsed Sam Clovis in the U.S. Senate primary and Matt Schultz in the Iowa 3rd District GOP primary race. Huckabee endorsed Robert Cramer in the 3rd District race. Perry endorsed Matt Whitaker in the U.S. Senate primary. All of those candidates lost.

Rastetter, who is president of the board that oversees Iowa's state universities, is a lead backer of Iowa ethanol ventures and a top donor to Ernst and Republican causes.

Since 1989, Rastetter has thrown a party every year, inviting everyone from neighbors to politicians with White House ambitions.

This year, more than 1,200 people were invited, including every member of the Legislature. Confirmed guests include Republican U.S. Sens. Ron Johnson of Wisconsin and Chuck Grassley of Iowa, Branstad, Lt. Gov. Kim Reynolds, and the presidents of Iowa's three state universities.