Congressional campaign stars

It's August, which means lawmakers are fanning out across the country to campaign for themselves and their colleagues.

Why it matters: A friendly senator or House member can help on the stump.

But only a handful can juice fundraising , draw a real crowd or make a mark with an endorsement.

And Democrats have more of them.

Zoom in: Axios asked strategists in both parties which lawmakers have enough star power to move voters, draw crowds or open wallets for candidates far from home.

There aren't many, but a few names came up again and again.

For Democrats: No one compares to former President Obama.

But among lawmakers, Sen.

Bernie Sanders (I-Vt.) has never been hotter, as progressives and democratic socialists take down one establishment-backed candidate after another.

In a twist, Sanders is seen by some Democrats as an asset not just in the primary — but also in the upcoming general election.

Sanders appeared in one of battleground House candidate Rebecca Cooke's closing primary ads in this week's Wisconsin primary.

Her other final ad pitched a Sanders idea — a moratorium on data centers.

"Public and private polls show that a lot of the working people Democrats have to win back respect Bernie Sanders because they want candid, populist leaders with the backbone to fight an economic status quo that has failed them," Democratic strategist and former Biden spokesperson Andrew Bates, who advises Cooke, told Axios.

"He's also an opponent of out-of-touch ideas that turn swing voters away, like 'defunding the police,'" Bates continued.