With nearly all votes counted, Hillary Clinton leads Bernie Sanders in the Kentucky Democratic primary by about 1,800 votes.
The Associated Press has said the race is too close to call. With 99.7 percent of all precincts reporting, Clinton is up 46.7 percent to 46.3 percent for Sanders.
If her lead holds, a narrow win in the Bluegrass State could give Clinton a slightly wider lead over Sen. Bernie Sanders, but would really be more of a moral victory as she seeks to turn her attention toward a likely general election race against de facto GOP nominee Donald Trump.
Secretary of State Alison Lundergan Grimes, a Clinton supporter, told CNN that based on her lead, Clinton is the "unofficial winner." There is no automatic recount process in Kentucky. A candidate would have to request a recount within 10 days, and would be responsible for all costs.
Oregon was also voting Tuesday, where the state's mail-in ballots were due by 11 p.m. ET. Trump was easily called the GOP winner there as the only remaining candidate in the race. The Democratic race was too early to call.
Even though the former secretary of state has an edge of more than 280 delegates over rival Bernie Sanders, a win in Kentucky would be Clinton's first primary victory since April.
The Vermont senator recently notched wins in Indiana and West Virginia, but by margins that did little to close the gap with Clinton. Still, her repeated losses spurred talk that Clinton would have difficulty uniting Democrats in the fall, and also exposed her weaknesses with younger voters and white, working-class men.
A Kentucky win is one Clinton fought hard for, campaigning heavily in the state. According to NBC News, it was the first state since March 15 where she outspent Sanders on the airwaves.
The Kentucky contest was a closed primary — meaning only registered Democrats, and not independents or crossover Republicans, could vote in the primary. Throughout the primaries, Clinton consistently has won such closed contests.
Sanders did well in more rural areas of the state — coal mining-heavy regions similar to those he captured last week in the West Virginia primary. Those are areas Clinton did well in versus Barack Obama in 2008. Since then, she has come under fire for comments suggesting she would begin to phase out the industry in favor of cleaner energy sources, and she also has become aligned with Obama's unpopular environmental policies in the region.
But Clinton did well enough in metro areas of the state like Lexington and Louisville to take the lead over Sanders
Kentucky's 55 pledged delegates will be split proportionally, and such a close finish means they each will get roughly the same number of delegates — again, not really enough to change Clinton's advantage over Sanders. He still needs to win about 66 percent of all remaining pledged delegates to hold a majority of them; when superdelegates are included that proportion climbs to around 84 percent.
Sanders has remained in the race despite nearly insurmountable odds of reaching the 2,383 delegates needed to clinch the Democratic nomination. Tensions escalated between the campaigns and the national party on Tuesday as the Sanders campaign doubled down on charges they had been unfairly treated at this past weekend's Nevada Democratic convention. There were tense confrontations between Sanders delegates and Nevada officials, and the state party chairwoman has said she since has received threats from Sanders supporters.