Vote counts released Thursday show the gap narrowing for a measure that would legalize medical marijuana.
It was failing by just 3,848 votes out of nearly 1.4 million votes counted. The proposal narrowed its deficit by more than 3,000 votes on Wednesday.
Proposition 203 was still too close for a race call by The Associated Press on Thursday.
The Arizona Secretary of State's office says county officials in the state counted about 69,000 ballots on Thursday. An estimated 221,000 early ballots and 83,000 provisional ballots remain to be counted. That could take days.
Proposals in 1996 and 1998 were approved but a problem with the wording blocked their enactment. A more sweeping 2002 proposal lost.
This proposal would allow the use of the drug only for serious diseases including cancer.