Last Wednesday, the Washington Post described the upcoming Wisconsin primary as "the Masada of the 'Stop Trump' movement," a reference to the Israeli hilltop where ancient Jews once made a desperate last stand against the Roman Empire.

One week and millions of dollars later, the state is looking more like the Stop Trump movement's Gettysburg. A Marquette University Law School poll released Wednesday shows Sen. Ted Cruz of Texas leading Donald Trump by 10 points in Wisconsin. With the state's primary scheduled for next Tuesday, that could prove to be an insurmountable deficit for Trump.

The gap is particularly significant because Wisconsin appears to be where a collection of conservative donors and institutions have mounted their last-ditch effort to deny Trump the nomination. The Republican front-runner has 736 of the 1,237 delegates he needs in order to win a clean majority and avoid a brokered convention when the Republican Party gathers July 18-21 in Cleveland. That leaves 501 delegates to go; Wisconsin, which is not a winner-take-all state, holds 42.

In the days and weeks before the Wisconsin primary, big-money groups on the right have geared up to rout Trump. Last week, the influential political action committee Club for Growth PAC formally endorsed Cruz, the first time the group has ever officially supported a presidential candidate. It followed up that show of support with a $1 million expenditure to air anti-Trump, pro-Cruz ads in Wisconsin.

Our Principles PAC, another major anti-Trump group, put up its own ad challenging the front-runner as well. And Wisconsin Gov. Scott Walker, a long-time favorite of the conservative donor network led by the billionaire brothers Charles and David Koch, endorsed Cruz earlier this week.

It's difficult to say with any certainty whether the sudden infusion of outside spending may helped swing the Wisconsin primary against Trump, but many Republican donors are likely celebrating the front-runner's change of fortune. If the candidate fails to secure 1,237 delegates, then the convention may be another opportunity for his opponents within the Republican donor network to select their own nominee.