In the Senate, Republicans need a net gain of six seats for a majority. They have obvious targets: seven Democratic-held seats in states carried by Romney.
South Dakota and West Virginia, where incumbents are retiring, look like easy pickups. Montana, where a little-known lieutenant governor has been appointed to fill a vacancy, may be another.
Democratic incumbents are running behind or (always trouble for an incumbent) below 50 percent in four Romney states -- Alaska, Arkansas, Louisiana and North Carolina.
The field seems to have widened to target states Obama carried in the 2012 presidential election. Gallup shows his approval down even more than the national average in each of them.
They include Colorado, Iowa, New Hampshire and even Michigan, which was a target state only briefly if at all.
Perhaps even Minnesota, the one state Ronald Reagan never carried, but which voted only 54 percent for Obama, or Oregon and Virginia, where incumbents seem strong but may have serious challengers.
Republicans surely won't win all or perhaps even most of these races. But they seem likely to make serious gains, with the only possible offsetting losses in Romney states Georgia and Kentucky.
I have said that prediction today is relatively easy, up to a point -- actually, two points.
One is that candidate quality matters in Senate races. Republicans lost winnable races in 2010 and 2012 with suboptimal (to put it politely) nominees. That could happen again.
The other point is that two-party competition is fierce and close. During Tip O'Neill's years in Congress, presidential candidates won the popular vote by an average 12 percent. Since he retired in 1986, the average has been 5 percent.
Republicans have won House majorities in eight of 10 elections starting in 1994. But they have never won more than 242 seats. In the eighteen elections from 1958 to 1992, Democrats never won less than 243.
So while it's easy to see the general drift, it's harder to peg which side will get those last few electoral votes or seats that make the difference between victory and defeat.