In case you were wondering how high the stakes are for the national right in the battle over Scott Walker’s recall, consider this: The Americans for Prosperity Foundation, a branch of the conservative group founded by the Koch brothers, is sinking at least $700,000 into ads in Wisconsin defending Walker’s record.

A source who tracks ad buys first noticed the expenditure, which has now been confirmed by a spokesman for the group.

The spot is a remarkable minute-long defense of Walker’s budgetary policies, including the controversial rollback of public employee bargaining rights, and interestingly, the ad mounts this defense without mentioning Walker’s name once.

What’s more, it also claims that Walker’s policies have been implemented without any “mass layoffs,” sounding a pro-worker message, despite the fact that national conservatives see Walker as their number one hero when it comes to breaking the back of the national labor movement:

Americans for Prosperity Foundation spokesman Levi Russell confirms to me that the $700,000 ad buy will fund this ad in various Wisconsin markets, and another ad to be unveiled next week. The current spot, which has run previously, doesn’t mention Walker because the ad is being funded by the group’s 501c3.

AFP invested heavily in last year’s battle over the recall of GOP state senators who supported Walker’s rollback of bargaining rights. AFP took some heat after it emerged that the group had sent out absentee ballots, in the districts of at least two state senators, that ended up misleading voters about the date of voting.

The group’s massive investment in the Walker recall fight is another reminder that for national conservative and Tea Party groups, the battle to defend Walker against recall has emerged as their number one national cause celebre.

As Andy Kroll reported recently, the Walker recall is a crucial, make-or-break moment for the Tea Party. Walker’s initial election was a major Tea Party victory, and the Tea Party is currently shrinking and a bit adrift. If Walker loses, it will be a major blow to the national movement. In this sense, the battle to save Walker may end up being seen as the Tea Party’s last stand.