Mason-Dixon continues to produce numbers out of Nevada. The latest polling is from the third congressional district.  The district encompasses suburban Clark County (Las Vegas) and leans ever-so-slightly toward the Democrats, with a PVI of D+2.  Partisan registration in the district is 46% Democrat, 37% Republican, and 17% Independent, though there is still a vestigial Southern Democratic component to Nevada's Democratic party.

Created in 2002, the 3rd District was represented for three terms by moderate Republican Jon C. Porter, who won a series of close contests in the district before falling to Dina Titus in 2008.

If the latest polling is correct, Titus is set to have a difficult time holding onto the district.  Titus is tied with former state Senator Joe Heck at 40% each, and leads real estate nvestor Rob Lauer 48%-32%.

Titus isn't being helped by the health care debate, as 47% disapprove of her vote for the recent health care bill, while 41% approve.

The obvious takeaway from this poll is that Titus is in trouble -- no incumbent can feel good about being below 50% in a poll against a relative unknown and a total unknown.  Being tied at 40% is atrocious news for an incumbent.

But the bigger takeaway is this:  Right now, Stu Rothenberg doesn't have Titus' district listed as competitive.  Charlie Cook has it leaning toward the Democrats, along with 23 other seats (15 are tossups and 1 leans toward the Republicans).  So the key questions are: (1)  How many Democrats thought to be in pretty decent shape by the professional prognosticators are actually in somewhat serious trouble and (2) How bad is it really for the Democrats remaining in the tossup category?