Massachusetts’ US Senate race may be the most closely watched election in the country, after the presidential one. That’s largely because of the candidates, both of whom became instant celebrities — Scott Brown for his stunning, Senate-changing victory in 2010, Elizabeth Warren for initiating the Obama administration’s consumer-finance protection bureau. The clash pitting the former model turned everyman against the gutsy law professor with her librarian glasses and no-nonsense haircut seemed destined to be uniquely memorable. In many ways, it has been. But with less than two months to the election, the contest must rank as a disappointment of sorts — not a dud, but not the dynamic exchange of ideas and visions that it might have been.

Tonight, with the first of four televised debates, all that could change. Both candidates have spent a year burnishing their images. But there are whole swaths of Senate business, such as the need for a specific plan to avoid the so-called fiscal cliff, along with Massachusetts priorities such as federal funding for medical research and clean energy, that haven’t been fully debated.

Warren talks about these issues, but her heart is clearly in consumer finance. Credit cards, student loans, and bank fees strike directly at the pocketbook, and no one can say that they aren’t relevant to the campaign. But Warren rarely expresses any confidence or expertise on other issues, and her framing argument — that the system is rigged — only emphasizes the one-note character of her presentation. For Warren, the struggle for consumer rights is almost a biographical story — it’s how she explains herself to Massachusetts — but there are risks in making the political feel so personal: It draws attention to her burning desire for vindication after Republicans blocked her nomination to head the agency she created.

Brown’s campaign is personal in a different way: He’s running on his charm, personality, and telegenic family. The reasoning seems to be that the more Brown registers as an individual, the less voters will remember that he’s a Republican, a big disadvantage in a Democratic state. Images can seem a higher priority than ideas: Brown’s campaign bought an ad congratulating Tim Wakefield and Jason Varitek on their service to the Red Sox.

Establishing Brown as an individual connects to a core argument for his Senate candidacy: He’s an avowed centrist in a chamber full of ideologues. Like Warren’s emphasis on consumer finance, Brown’s bipartisanship is clearly relevant to this moment. But what Brown doesn’t say is how he plans to use his centrist leverage. Even when he seems about to discuss an issue, such as taxes, he retreats to bromides — he’s for the middle class — and vagueness — he’s against higher taxes. In fact, he voted against both Democratic and Republican tax legislation without revealing what he’s for. His next ad had him back behind the wheel of his truck, bemoaning political insiders.

It’s still hard to say what, concretely, each one is going to deliver for Massachusetts.

This campaign has been dominated by the candidates’ vividly contrasting personalities. They’re stars, all right. But it’s still hard to say what, concretely, each one is going to deliver for Massachusetts.