This conclusion is less surprising than the source (Mark Halperin) and the venue (Time magazine):

Under pressure, the Democrats are cracking. On both ends of Pennsylvania Avenue, there is a realization that Nancy Pelosi’s hold on the speakership is in true jeopardy; that losing control of the Senate is not out of the question; and that time, once the Democrats’ best friend, is now their mortal enemy. Since January, when Scott Brown won Ted Kennedy’s Massachusetts Senate seat, the President’s party has tried to downplay in public what its pollsters have been saying in private: that Obama’s alienation of independents and white voters, along with the enthusiasm gap between the right and the left, means that Republicans are on a trajectory to pick up massive numbers of House and Senate seats, perhaps even to regain control of Congress.

Put another way, right now it is very likely that no GOP Senate incumbents lose. This secures Louisiana and North Carolina. At this point, the GOP appears near-certain to keep New Hampshire, Florida, Ohio, Missouri, and Kentucky.

This means they keep their floor of 41 votes. Now throw in the races that are already near-certain, like North Dakota, Arkansas, Indiana, Colorado, Delaware.

This puts them at 46. Toomey’s pretty darn likely to pick up Pennsylvania. That’s 47. Sharron Angle trailed the last poll in Nevada, but Harry Reid’s been consistently stuck below 44 for more than a year. Throw her in for 48.

The GOP probably ought to win Illinois, but that one can’t be taken for granted after Mark Kirk’s rough couple of weeks. But figure there’s a wave of revulsion at Illinois Democrats, the party of Rod Blagojeich and the unpopular governor, Pat Quinn. Kirk’s win would put it at 49.

The ones that are looking competitive and hard to predict right now are California, Wisconsin, and Washington. (West Virginia could conceivably get competitive, but there’s no real evidence of that yet.) If the Senate were split 50-50, Vice President Joe Biden would be the tie-breaking vote, so Republicans really need to win 51 to control the Senate. They need nothing to go wrong*, and for a good national wave to add momentum to two out of these four: Carly Fiorina, Ron Johnson, Dino Rossi, or their nominee in West Virginia. But if the GOP is really is on course to add 7 to 10 seats, they should be on pace for monster gains in the House.

* You are permitted to laugh loudly and at length at that caveat.