A new national poll released on the eve of the two major political party conventions indicates Democratic challenger Joe Biden with a smaller lead over President Trump than most other live telephone operator surveys show.

WHAT THE LATEST FOX NEWS POLL SHOWS IN THE WHITE HOUSE RACE

The ticket of Biden and Sen. Kamala Harris of California – whom the former vice president and presumptive Democratic nominee named as his running mate last week – tops the ticket of Trump and Vice President Mike Pence 50%-46% among registered voters in a CNN survey conducted Aug. 12-15. The 4-point advantage for the Democratic ticket is right at the poll’s margin of error of plus or minus 4 percentage points.

But a new ABC News/Washington Post national poll released hours later indicated Biden holding a 12-point, 53%-41% lead over the president among registered voters.

The survey -- which was conducted on the same days as the CNN poll -- also showed the former vice president topping Trump by 10-points -- 54%-44% -- among likely voters.

An average of all the latest national general election matchup polls compiled by Real Clear Politics indicated Biden topping Trump by 7.5 points.

Biden’s lead over the president in the CNN poll widens to 53%-46% among the nearly three-quarters of those questioned who said they’re extremely or very enthusiastic about voting this fall. But the former vice president’s edge of Trump shrinks to just 1 point – 49%-48% – among those polled who live in 15 general election battleground states.

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The CNN poll – which was released Sunday – questioned 987 registered voters nationwide using live telephone operators.

The ABC News/Washington Post poll -- which was released early Monday morning -- questioned 1,001 adults nationwide using live telephone operators. The survey's sampling error is plus or minus 3.5 percentage points.