The hope was that the change would increase voter participation.
The open primary could be seen as good for voter participation.
Voter participation in these elections is light, he said, with 50 to 60 coming out to vote.
The benefits of voter participation go beyond any single candidate.
If all goes well, they say, voter participation should increase, particularly among younger voters.
In the 26 March general elections, voter participation was reported at 89.8%.
Impact on voter participation was, by that time, less dramatic.
The open primary could also be viewed as bad for voter participation.
There is also a question about voter participation among the 44 million in the electorate.
Last month voter participation was as high as 65 percent.