First Lady Jill Biden made a brief stop in Ankeny Wednesday to promote the president's $3.5 trillion "Build Back Better" plan as it faces intense negotiations in Washington.The first lady joined Rep. Cindy Axne, D-Iowa for an event promoting the plan at the Des Moines Area Community College campus.Biden pushed for extending the child tax credit and emphasized provisions in the plan expanding child care and paid leave, as well as make community college free."This is infrastructure," she said. "Investing in working families is the best way that we are going to recover from this pandemic."The first lady's visit comes as the president makes a push to persuade members of his own party and the public on the merits of the plan.The president doesn't need Republican support, but with a tenuous Democratic majority in the Senate, he has to convince skeptical Democrats, like Sen. Joe Manchin of West Virginia.Manchin has balked at the plan's price tag. "Hit the pause button," Manchin said at an event in early September. "Let's step back. Let's see what happens."The first lady did not speak to the media Wednesday, but Axne did, urging members of her own party to back the president."First and foremost, we don't even know if ($3.5 trillion) is going to be the final amount," Axne said. "Secondly, this is over a decade. So this is not spending in one year. Third, it's about an investment. This is is an investment in our country."The Republican National Committee commented on the first lady's trip to Ankeny even before her plane touched down in Iowa.In a statement, the RNC said "(n)o visit from Jill Biden will erase the fact that the Biden administration is actively seeking to take away the rights of Hawkeye Staters with their unconstitutional executive orders," referring to the President's recently-announced mandate requiring many workers to either get vaccinated or submit to weekly COVID-19 tests."Prior to arriving in Ankeny, the first lady was in Wisconsin, holding an education event at a Milwaukee school.