A conservative activist’s research estimates 12 million Democrats crossed over to vote in the 2016 Republican primary, accounting for roughly 38 percent of the total votes cast. That revelation, published on conservative blog RedState.com, has renewed calls for Alabama to close its primaries.

Alabama is one of 20 states around the country with “open primaries” for congressional and state races, and one of 16 states with open presidential primaries. This means that while voters have to choose which primary they will vote in when they arrive at their polling precinct, they do not have to register with one party or the other ahead of time.

Critics of open primaries argue that such a system can become particularly problematic in states like Alabama where one party is dominant.

During the 2014 election cycle, for example, liberal groups sought to take advantage of Alabama’s open system by working to get traditionally Democratic voting blocs to the polls to vote not for Democrats, but for their chosen Republicans.

Some Republicans also blame the open primary system for the election of current GOP Gov. Robert Bentley, who was heavily aided by the traditionally Democratic-leaning teachers union.

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Alabama Republican Party chairwoman Terry Lathan told Alabama sports website and liberal political blog al.com that the current system is analogous to Alabama football coaches being able to pick the players on Auburn’s team, or vice versa.

“We do not want people from another party picking our team and I’m sure they wouldn’t want us picking their team,” she said. “It’s pretty much that simple.”

The Alabama Republican Party Executive Committee, a large panel of party activists from around the state who set party policy, seem to agree with Mrs. Lathan. Seventy-six percent of them voted for closed primaries earlier this year.

That cannot be done, however, without a vote of the legislature. Sen. Tom Whatley sponsored a bill to close Alabama’s primaries, but it failed to pass.

Meanwhile, some Republicans have criticized efforts to close the state’s primaries, saying such a move would send the wrong message and hurt the party’s ability to attract new voters, particularly minorities.

A record 11 black Republicans sought elective office in Alabama during the 2014 cycle, compared to just one in both 2010 and 2012.

One of those candidates, Darius Foster, has voiced concerns that closing Alabama’s primaries could be a shortsighted move.

“Dispelling the myths about minority conservatives will take years to accomplish,” he said.