A lot has happened in the presidential race since we last handicapped the Electoral College landscape in January. Earlier this week, we revisited the race and took a stab at what it would look like if former Massachusetts Gov. Mitt Romney won the GOP nomination.

Now, we'll look at what would happen if former House Speaker Newt Gingrich -- or another more conservative Republican in the field, such as Texas Gov. Rick Perry -- were to win the nomination.

While Romney has sought to define himself as a conservative in the race, his more moderate campaigns for U.S. Senate and Massachusetts governor hold appeal to independents that a conservative Republican might not be able to offer. That accounts for the differences in how we're handicapping the two potential 2012 Republican nomination scenarios.

Our baseline analysis in January pitted Obama against a hypothetical, generic Republican nominee; we acknowledged that the actual nominee might be stronger, or weaker, than the hypothetical one. Based on interviews with political observers in the competitive states, we concluded back then that Republicans had 219 of the required 270 electoral votes either solidly or leaning in their direction, the Democrats had 215, and 104 votes were in 10 states we rated tossups.

Under scenario one -- if Romney or former Utah Gov. Jon Huntsman won the nomination -- the Republican would find himself with 223 electoral votes in the safe, likely or lean Republican category, compared to 192 in the safe, likely or lean Democratic category for Obama. The winner would need to draw from 123 electoral votes in 10 states considered tossups.

Under scenario two, Gingrich or another staunch conservative would be in a noticeably weaker position. In this scenario, the GOP nominee could count on 191 electoral votes in safe, likely and lean Republican states, while Obama could count on 237 electoral votes in safe, likely and lean Democratic states. Nine tossup states with 110 electoral votes would decide the winner.

Bottom line: As things stand today, choosing a more conservative candidate than Romney as the GOP nominee throws 32 electoral votes from the Republican column to the tossup column, and 45 electoral votes from tossup into the Democratic camp.

The recent boomlet for Gingrich has certainly improved his standing against Obama, judging by Quinnipiac polls of three swing states released today. However, this late surge still fits with the calls I made prior to the poll's release.

In Florida, which I call a tossup, Romney edges Obama, 45 percent-42 percent, while Obama edges Gingrich, 46 percent-44 percent. In Ohio, another tossup, Romney and Gingrich both narrowly lead Obama, 43 percent-42 percent respectively.

Obama is in better shape against Gingrich in Pennsylvania, a state we label a tossup if Romney is the nominee and lean Democratic if Gingrich is the nominee. In the Keystone State, Quinnipiac finds Obama leading Romney, 46 percent-43 percent, but leading Gingrich by eight points, 48 percent-40 percent.

In the non-Romney scenario, Obama could win a second term by adding just Wisconsin, Ohio and Nevada from the tossup list; or only Florida and New Hampshire; or else Wisconsin, Nevada, Iowa, Colorado and New Hampshire. None of these paths to victory are necessarily easy for a president stuck with a weak economy and an unhappy electorate, but this path appears to be -- for now at least -- much more favorable to the incumbent than the one in which Romney is the GOP nominee.

One safe Republican state shifts to likely Republican if Romney or Huntsman isn't the nominee: Arizona. (Remember, though, that likely Republican still isn't considered competitive in the big picture.) We considered moving Georgia from safe Republican to likely Republican as well, but it is Gingrich's home state, so we'll hold off on that switch for now. Two other states shift from likely Republican to lean Republican -- Indiana and one congressional district in Nebraska.

Meanwhile, three states would shift from lean Republican to tossup if Romney or Huntsman isn't the nominee (New Hampshire, North Carolina and Virginia) while four shift from tossup to lean Democratic (Maine, Michigan, New Mexico and Pennsylvania).

Finally, three lean Democratic states would shift to likely Democratic: Minnesota, New Jersey and Oregon.

Of course, much will change between now and November 2012. It's possible that Gingrich will make himself more appealing to independent and moderate voters, and that the Electoral College landscape for Gingrich will ultimately look more like it does now for Romney. But after decades on the national scene as a polarizing figure, We think the burden is on Gingrich to demonstrate that he can overcome his political baggage in a way that improves his standing with independents and moderates.

A reminder of a few notes on our handicapping system:

States deemed lean Republican, tossup or lean Democratic are considered competitive; states in other categories are not, at least for now.

Unlike our handicapping from last January, we now have enough confidence in the electoral landscape to rank-order the states within each category, except for safe Democratic and safe Republican. So, beyond the safe categories, the list of states can be viewed as a continuum between the states most likely to go Republican (at the top) and the states most likely to go Democratic (at the bottom).

Unlike all other states, Maine and Nebraska award one electoral vote to the winner of each of the state's congressional districts. Where appropriate, we've split out congressional district electoral votes that differ in handicapping category from the state as a whole.

SCENARIO 2: Someone other than Romney or Huntsman is the Republican nominee

(Number of electoral votes are in parentheses)

Safe Republican (158 electoral votes)

Alabama (9), Alaska (3), Arkansas (6), Georgia (16), Idaho (4), Kansas (6), Kentucky (8), Louisiana (8), Mississippi (6), Montana (3), Nebraska (4 of 5 electoral votes), North Dakota (3), Oklahoma (7), South Carolina (9), South Dakota (3), Tennessee (11), Texas (38), Utah (6), West Virginia (5) and Wyoming (3)

Likely Republican (11)

Arizona (11)

Lean Republican (22)

Indiana (11)

Nebraska (1 of 5 electoral votes)

Missouri (10)

Tossup (110)

North Carolina (15)

Virginia (13)

New Hampshire (4)

Colorado (9)

Florida (29)

Iowa (6)

Nevada (6)

Ohio (18)

Wisconsin (10)

Lean Democratic (45)

Michigan (16)

Maine (4)

Pennsylvania (20)

New Mexico (5)

Likely Democratic (43)

Minnesota (10)

New Jersey (14)

Oregon (7)

Washington state (12)

Safe Democratic (149)

California (55), Connecticut (7), Delaware (3), District of Columbia (3), Hawaii (4), Illinois (20), Maryland (10), Massachusetts (11), New York (29), Rhode Island (4) and Vermont (3)

Votes from states that are safe, likely and lean Republican: 191

Votes from Tossup states: 110

Votes from states that are safe, likely and lean Democratic: 237