First, to set the stage, here's what the map looked liked in 2012 when Barack Obama won 332 electoral votes to Mitt Romney's 206.
Now, here's our first take on the 2016 map -- with states solidly Republican or Democrat marked in red or blue and any states that either lean toward one party or are true tossups in grey.
That map puts Clinton at 201 electoral votes and Trump at 164. A candidate needs 270 to win.
The 13 states that are not solidly behind either of the candidates account for 173 electoral votes. Of those, four (51 electoral votes) we rate as lean Democratic. Seven, totaling 95 electoral votes, are pure toss ups. Two -- 27 electoral votes -- lean Republican.
Let's go through each category and explain a bit of our thinking.
Lean Democratic (51 electoral votes)
* Colorado (9): Colorado is similar to Nevada (and a number of other states) in that the electorate has grown less white over time. It backed Obama in 2008 and 2012 after mostly picking Republicans since 1968 (the exception being Bill Clinton in 1992). Republican Cory Gardner won his Senate challenge in 2014 -- a Republican wave election -- by a narrow margin. There isn't much reason at this point to think that Republicans will re-take the state.
* Michigan (16) and Pennsylvania (20): Michigan and Pennsylvania have each voted Democratic since 1992. The electorate in each in 2012 was about an eighth black, a group that strongly supports Clinton. Trump's campaign hinges on his ability to appeal to blue-collar white voters in Rust Belt states like these two, luring Democrats to his candidacy and turning out people who don't normally vote. So far, there's not much evidence Trump has turned out new voters, and the number of working-class whites who still vote Democratic has dwindled. (In 2014, white Midwesterners without a college degree preferred Republican House candidates by almost 30 points.) Unless Trump shows that he can move these numbers, these states are likely to stay blue.
* Nevada (6): Nevada's history of voting for the Democratic candidate isn't long, but the state backed Obama each time he ran by decent margins. What's different this time is that the state's Hispanic vote continues to grow. In 2004, 77 percent of the state's voters were white, according to exit polls. By 2012, that figure was 64 percent -- and the percent that was Hispanic grew from 15 to 19 percent of voters between 2008 and 2012. With Trump's bad numbers among Hispanic voters, that trend suggests that the state will stay blue.
Toss Up (95 electoral votes)
* Florida (29): In 2008, Obama won the Sunshine State with 51 percent -- a margin just shy of 250,000 votes (out of 8.2 million cast). Four years later, he won even more narrowly -- taking 50 percent to Romney's 49 percent, a gap of just more than 60,000 votes out of 8.3 million cast. Trump's strength in Florida in the Republican primary coupled with his high visibility and long connections to the state make it an interesting one for him. His biggest problem? Almost four in ten residents are either black (15.3 percent) or Hispanic (22.9 percent).
* Iowa (6): There's a tendency to assume Iowa is a Democratic state because Obama carried it by 10 points in 2008 and six points in 2012. But, as of today, Iowa has a Republican governor, two Republican Senators and three (out of four) Republican members of Congress. And, don't forget that as recently as 2004 George W. Bush won the Hawkeye State. For Trump to win, he has to make the upper Midwest competitive and that very much includes Iowa.
* New Hampshire (4): New Hampshire, like much of the northeast, used to be solid Republican territory. Since 1988, it's either gone strongly for the Democratic candidate or has been a toss-up (as in both of George W. Bush's elections). What puts New Hampshire into the toss-up category in 2016 is its large proportion of independents. In 2012, that group made up more than 4-in-10 general election voters, and went narrowly for Obama. Recent polls suggest that Trump has a big lead with independents, which could flip the state.
* North Carolina (15): After a narrow Obama win in 2008, Romney took the Tar Heel State back -- again, narrowly -- in 2012. The fact that nearly 30 percent of the state's population is either black or Hispanic makes it an immediate Clinton target given how dismal Trump's numbers are among both groups. Add that to the fact that the Research Triangle (Raleigh, Chapel Hill and Durham) is populated by lots and lots of affluent, highly educated whites -- two groups that have proven the least willing to be persuaded by Trump's message -- and the state is a toss up through and through.
* Ohio (18): Republicans were thrilled when a Quinnipiac University poll popped up earlier this month showing Trump leading Clinton 43 percent to 39 percent in the Buckeye State. The state has been friendly to Republicans of late with John Kasich -- remember him? --winning by 31 points in his 2014 re-election race. (That margin was due, at least in part, to the fact that Democrats ran one of their worst candidates of the cycle against Kasich.) Like Michigan and Pennsylvania, working class whites are all over Ohio and, if Trump has a path to victory, it's by turning them out in droves. Unlike Michigan and Pennsylvania, a Republican has won Ohio at the presidential level this century.
* Virginia (13): When Obama won here in 2008, he became the first Democrat to do so since Lyndon Johnson in 1968. Given the history, 2008 might have been written off as a fluke. But, when Obama carried Virginia again in 2012 -- by a convincing four points -- he drove home the new reality of the Commonwealth as a swing state. Trump's very narrow primary win over Marco Rubio likely presages his problem in a general election against Clinton here. Trump got killed in northern Virginia, the vote-rich area populated, generally speaking, by lots and lots of establishment Republicans. Clinton will target northern Virginia relentlessly from now until election day in hopes of peeling away those Republicans from Trump.
* Wisconsin (10): If there is any swing-ish state in the country moving toward Republicans, it's Wisconsin. It was the 10th closest vote -- by percentage -- between Obama and Romney in 2012 and recent victories -- all three of them -- by Gov. Scott Walker suggest the state is increasingly open to the conservative message. Wisconsin is also heavily white -- 83 percent of the population -- which means Trump doesn't start with the high hurdle he does in other states with larger minority communities.
Lean Republican (27 electoral votes)
* Arizona (11): Polling in the state is extremely limited but, based on its considerable Latino population (30 percent of population) this is a state that the Clinton campaign will take a hard look at over the next few months. Eight years ago, Obama was making noise about targeting Arizona but ultimately took a pass due to McCain's home state edge. Four years later, the state was largely off limits to Democrats as Gov. Jan Brewer's 2010 decision to sign into law a very controversial immigration bill polarized the electorate along racial lines -- with whites almost exclusively voting Republican. The state's Hispanic population continues to grow, however, and Trump's candidacy would seem to be a major motivator to turn out Latinos.
* Georgia (16): This is another state in which demographic shifts are moving things in Democrats' favor. In 2012, Georgia was the 12th closest state by percentage as Romney won it by eight points. It was the 8th closest state in 2008. And, polling in a Trump-Clinton matchup suggests it might be truly competitive in 2016; Trump has a narrow single digit edge in two recent independent surveys. One caveat: There was much excitement among Democrats in 2014 about Michelle Nunn's Senate candidacy in the Peach State. She wound up losing by eight points to a wealthy businessman making his first run for elected office. Sound familiar?
For an explanation of this tool, read this.