Story highlights Cruz and Sanders are the leaders in Wisconsin ahead of the state's primaries

Kasich and Sanders are the two best-performing candidates in the general election

Washington (CNN) Ted Cruz holds a wide lead over Donald Trump in Wisconsin less than a week from the state's primary, and Bernie Sanders has a narrow edge over Hillary Clinton, a new Marquette University Law School poll shows.

Cruz, the Texas senator, tops the Republican field with 40% support, compared to Trump's 30% and Ohio Gov. John Kasich's 21%.

Sanders, meanwhile, has 49% backing to Clinton's 45% in the Democratic race.

The 2016 presidential campaign has descended on Wisconsin ahead of the state's April 5 contest. It's the only major primary before New York's two weeks later, and is seen as a gauge of momentum for the GOP establishment's anti-Trump efforts.

The poll also showed that Sanders beats all Republican candidates in head-to-head matchups in the Badger State. He topped Kasich, 46% to 44%, and crushed Cruz, 52% to 29%, and Trump, 54% to 35%.

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