You may go along and keep your head up your ass denying it but it is quite likely that a significant number of illegal votes were cast by noncitizens.
n 2014, the academic journal Electoral Studies published a paper by three scholars who analyzed the results of a large survey conducted by a group at Harvard University. This study also made use of polling data from YouGov and voter registration and turnout data from Catalist, a firm that equips “progressive organizations” with data to help them “persuade and mobilize” people.
In this 2008 survey of 32,800 respondents, 339 identified themselves as non-citizens, and 38 of these non-citizens checked a box that said “I definitely voted” in the 2008 general election or were recorded in the Catalist database as voting in that election. At face value, this means that 11.2% (38/339) of non-citizens voted in the 2008 election.
Applying this 11.2% figure to the Census Bureau’s estimate of 19.4 million adult non-citizens in the U.S., this amounts to 2.2 million non-citizens who voted illegally in the 2008 election. After weighting these results and accounting for margins of error, the authors estimated that a maximum of 2.8 million non-citizens voted in 2008.
http://www.washingtontimes.com/news/2017/jun/19/noncitizen-illegal-vote-number-higher-than-estimat/
http://www.justfactsdaily.com/substantial-numbers-of-non-citizens-vote-illegally-in-u-s-elections/