The two headline races in Nevada are neck and neck, a poll released Thursday shows. 

The Suffolk University poll shows Republican Rep. Joe Heck tied with Democrat Catherine Cortez Masto at 37 percent. Fourteen percent of likely voters say they haven’t decided on who should replace retiring Democratic Minority Leader Harry Reid. 

The Rothenberg & Gonzales Political Report/Roll Call rates the race a Tossup. 

[In Nevada, Heck’s Challenge Might Be Getting Tougher]

In the presidential race, Democrat Hillary Clinton leads her Republican rival Donald Trump by 2 percentage points, 44 percent to 42 percent, but that’s within the margin of error of 4.4 points. 

David Paleologos, director of the Suffolk University Political Research Center in Boston, said Clinton’s 13 percentage point lead in Clark County, home to Las Vegas, is the difference in the race. 

“In this instance, what happens in Vegas doesn’t stay in Vegas — it affects the whole state,” Paleologos said in a news release.  

[Roll Call’s 2016 Election Guide: Senate]

Nevada is considered a winnable state for Clinton. Barack Obama carried the Silver State by 7 points in 2012 and by 12 in 2008. Nate Silver’s FiveThirtyEight website, when factoring in the new Suffolk University poll, gives Clinton a 69.1 percent chance of winning the state if the election were held today.  

The poll was conducted by telephone August 15-17 among 500 likely Nevada voters.