Welcome to Countdown 2024 ... there are now 56 days until the election.  We have conservative political titans Bill Kristol and Stuart Stevens coming up on today's show ... where the focus will be all about debate night ... in what could prove to be one of the most pivotal nights of this presidential campaign.

But first let's take a quick spin around the political world for the latest....

Tonight's debate between Kamala Harris and Donald Trump in Philadelphia is the ONLY one scheduled before election day ... so the stakes are especially high.  In a likely attempt to get under the skin of the former president, Vice President Harris is bringing two former Trump White House staffers to the debate tonight, as her guests.  One of them is former Trump communications director Anthony Scaramucci ... we'll be talking with The Mooch here on Countdown on Friday!

Donald Trump called into NBC News this morning for a brief interview ... saying he "doesn't know what to expect" from Harris tonight, given her recently changing positions on several key issues.  Trump campaign sources say the former president won't try to hit Harris for "flip-flopping," ... but rather attempt to tie her to her most liberal positions on issues like immigration and fracking.

In some non-presidential campaign political news ... the House Republican majority put forward a spending bill that would keep the federal government up-and-running ... in exchange for approving a bill that would require voters to present proof of American citizenship.  It now looks like that gambit will fail ... and the government will be in danger of shutting down at the end of this month. 

The record for a TV audience watching a presidential debate came in 2016 when Hillary Clinton squared off against Donald Trump ... and an estimated 84-million Americans tuned in.  Tonight's Trump-Harris debate could eclipse that.

Today's guests on Countdown:

-Bill Kristol has been a presence in national Republican politics since 1970 when he was an intern at the Nixon White House.  He went on to work in the Reagan and George H.W. Bush administrations ... and eventually founded The Weekly Standard.  Kristol now finds himself at The Bulwark.

-Stuart Stevens was in the leadership of George W. Bush's 2000 campaign and helped to prep the eventual president (and eventual vice president Dick Cheney) for debates that year ... Stevens has served as a media consultant to countless Republican campaigns, and is now an advisor to the Lincoln Project.