National Dems are bullish about expanding their Senate majority, given that they're dramatically out-raising the GOP and that they have the Republicans on defense in multiple states.

And here comes the first wave of ads from Dem Senate candidates, a sign that Dems are aggressively shifting into general election mode, even if the presidential race hasn't quite finished yet.

Here's the new ad from Jeanne Shaheen, who is running ahead of incumbent John Sununu in the New Hampshire Senate race:

More ads after the jump.

Here's a spot from Rep. Mark Udall, who is narrowly ahead in the open Colorado race:

Here's a 60-second ad from Rep. Tom Udall, cousin of Mark Udall, who is currently way ahead in the open New Mexico Senate race:

And here's Tom Udall's 30-second spot: