National Democrats made their first advertising buy for New Mexico's Senate race on Monday, sending money to defend another member while already under pressure to compete on a challenging ticket.

The Democratic Senatorial Campaign Committee purchased about $96,000 worth of ad time in New Mexico from tomorrow through the end of the month as part of a joint ad buy in support of incumbent Sen. Martin Heinrich, according to AdImpact data.

More about the race: Heinrich is seeking a third term in traditionally blue New Mexico, but faces a Republican challenger, Nella Domenici, who has deep roots in the state as the daughter of longtime former New Mexico Republican Senator Pete Domenici.

There has been very little activity from outside groups in the New Mexico race so far, and while the DSCC's ad buy could be a preemptive defensive measure, it could also reflect Democrats' growing concerns about a potentially expanding map.

Here's how Republicans compare: The group's GOP counterpart, the National Republican Senate Committee, spent about $1.4 million on the race in a joint ad buy with Domenici and began running ads in August; The NRSC saw its largest bookings the week of Oct. 8, when it ran about $347,000 worth of advertising, including ads criticizing Heinrich's record on immigration and crime.

Since the start of 2024 and including bookings through Election Day, Democrats have outsold Republicans by a total of $7.3 million to $6.2 million in advertising for the New Mexico Senate race; The candidates account for most of the advertising: Heinrich's campaign spending is about $5.9 million, Domenici's campaign spending is about $4.6 million, not including joint ad purchasing with the NRSC.