Following her third-place finish in the Iowa caucuses on Monday, an old tweet from Republican presidential candidate Nikki Haley could come back to vex her campaign. In the resurfaced tweet posted on April 6, 2020, Haley cheered Bill Gates for putting up some of his billions to fund the production of COVID vaccines. “Thank you [Bill Gates] for donating billions of dollars to construct factories that will manufacture the seven most promising vaccines,” the former South Carolina governor posted. “This will keep us from losing any time as potential vaccines move through the clinical trial process…