I'm Margaret Brennan in Washington, and this week on Face the Nation, the diplomatic dance between the U.S. and Iran continues as Ukraine makes an impassioned plea for more help from the U.S.

We spoke exclusively with Ukrainian President Blodomier Zelensky, who issued a warning.

When we know that Russia prepares a big massive attack, definitely.

And urgently requested anti-ballistic missile weaponry from the U.S.,

whose supply is already stretched thin by that war with Iran.

Back home, as midterm matchups prepare for their November contests,

does character count anymore when it comes to politics?

We'll talk with former Vice President Mike Pence, as well as Connecticut Democratic Senator Chris Murphy.

They both have new books out and they both have thoughts on the future of their respective political parties.

We'll also hear from the outgoing head of the UN's World Food Program, Cindy McCain, on

the difficulty of feeding the world in challenging times.

It's all just ahead on Face the Nation.

Good morning and welcome to Face the Nation.

As we await developments in the back and forth between the U.S. and Iran over a framework for a truce in the now three-month-long war, CBS News has learned that the

president made further edits to the U.S. proposal on Friday, and mediators now wait on Iran's

response. We begin today with Ukrainian fears that Russia will soon stage a massive attack on

Kiev, which sources tell CBS News could include strikes on the presidential office and government

buildings. When we spoke exclusively to Ukrainian President Vladimir Zelenskyy on Friday,

he told us about the increased attacks from the Russians in recent weeks and the

dire need for assistance from the U.S.

We think that we will have a big attack from Russian side, using drones, using cruise missiles,

and ballistic.

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