armed forces stationed outside of their state of residency, may register and vote under the Uniformed and Overseas Citizens Absentee Voting Act (UOCAVA). Almost half the states require these ballots to be returned by mail. Other states allow mail along with some combination of fax, or email; four states allow a web portal. A significant measure to prevent some types of fraud has been to require the voter's signature on the outer envelope, which is compared to one or more signatures on file before taking the ballot out of the envelope and counting it. Not all states have standards for signature review. There have been concerns that signatures are improperly rejected from young and minority voters at higher rates than others, with no or limited ability of voters to appeal the rejection. For other types of errors, experts estimate that while there is more fraud with absentee ballots than in-person voting, it has affected only a few local elections. Following the 2020 United States presidential election, amidst disputes of its outcome, as a rationale behind litigation demanding a halt to official vote counting in some areas, allegations were made that vote counting is offshored. Former Trump Administration official Chris Krebs, head of the Cybersecurity and Infrastructure Security Agency (CISA) during the election, said in a December 2020 interview that, "All votes in the United States of America are counted in the United States of America." One documented trend is that in-person votes and early votes are more likely to lean to the Republican Party, while the provisional ballots, which are counted later, trend to the Democratic Party. This phenomenon is known as blue shift, and has led to situations where Republicans won on election night only to be overtaken by Democrats after all votes were counted. Foley did not find that mail-in or absentee votes favored either party. Early voting Early voting is a formal process where voters can cast their ballots prior to the official Election Day. Early voting in person is allowed in 33 states and in Washington, D.C., with no excuse required. Voting equipment The earliest voting in the US was through paper ballots that were hand-counted. By the late 1800s, paper ballots printed by election officials were nearly universal. By 1980, 10% of American voters used paper ballots that were counted by hand, which dropped below 1% by 2008. Mechanical voting machines were first used in