Independent presidential candidate Evan McMullin launched his candidacy on August 8, 2016. He got on the ballot in eleven states. In those eleven states, he received 510,002 votes, and the total presidential vote in those eleven states was 21,004,501. Therefore, in the states where he was on the ballot, he received 2.43% of the total valid votes cast.
He was not on the ballot in Michigan, Pennsylvania, or Wisconsin. If those states had voted for Hillary Clinton instead of Donald Trump, Hillary Clinton would have received a majority of the electoral college votes.
If McMullin had been on the ballot in Michigan, Pennsylvania, and Wisconsin, and if his support in those states had matched his support in the states in which he was on the ballot, then he would have received, respectively: Michigan 116,623; Pennsylvania 148,916; Wisconsin 71,767. Those totals are far larger than the margin by which Trump defeated Clinton in all three states. The margins between Trump and Clinton were: Michigan 10,704; Pennsylvania 44,292; Wisconsin 22,748.
McMullin’s campaign focused on persuading Republicans to vote for McMullin instead of Trump. It is reasonable to assume that where McMullin was on the ballot, a large majority of the people who voted for him were voters who would otherwise have voted Republican for President. Therefore, it is reasonable to believe that if restrictive ballot access laws had not kept McMullin off the ballot in Michigan, Pennsylvania, and Wisconsin, Hillary Clinton would now be President.
An actual example exists for Minnesota. Clinton carried Minnesota by 44,765 votes. McMullin was on in Minnesota and got 53,076 votes there.
McMullin had the capacity to complete petitions in states in which 5,000 signatures were required. He successfully got that many valid signatures in Kentucky and Virginia, both of which require 5,000. Pennsylvania only required 5,000 signatures, and Wisconsin only required 2,000, but McMullin couldn’t qualify in those two states because the deadlines were too early. Pennsylvania’s was August 1 and Wisconsin’s was August 2.
States could have had late August or early September petition deadlines, without harming election administration. In 2016, these six states had September deadlines: Arizona, Florida, Kentucky, Mississippi, North Dakota, and Rhode Island (the Florida deadline was the minor party deadline, not the independent deadline). These states had deadlines in the last week of August: Idaho, Oregon, Virginia, and Wyoming.