Each state's delegate allocations are slightly different, but they are all proportional. Candidates get a chunk of delegates for winning statewide, even more if you top 50 percent, which is unlikely in most cases. Then, in most cases you can win delegates by winning or coming second in congressional districts (or, for Texas Democrats, state Senate districts).
Delegate figures for Democrats do not include “superdelegates” – party leaders who can vote for whomever they want, regardless of the voting outcome in their states.
Texas
Republicans (155 delegates) – Ted Cruz has to win this state to keep his candidacy alive, and polls indicate he could do it – but a GOP early voting surge could indicate new voters attracted by the Donald Trump phenomenon. The Trump campaign believes that in urban areas such as Dallas, Houston and San Antonio, it can pull in new voters and mitigate Cruz’s strength among the traditional suburban and rural Republicans who swept him into office and keep him popular within his party.
Keep an eye on returns from East Texas, where voters could be more friendly to Trump’s aggressive immigration rhetoric. How the Mexican border regions vote will also be a fascinating case study.
If Marco Rubio wants to break 20 percent statewide to get into the delegate mix, he’s going to have to do well in cities like Dallas and could pick off delegates by winning some “blue” congressional districts. Cruz needs to run up the score in the Houston area, his hometown.
Democrats (222 delegates) – Hillary Clinton’s campaign has assiduously worked the heavily Latino border areas, and ran ads in El Paso and far South Texas. Watch to see if that pays off, or if the exit poll in Nevada is a sign that Bernie Sanders is improving among Latinos.
Keep an eye on Austin area districts, where Sanders has a chance to rally white liberals and snag some delegates to take home – because a statewide win is incredibly unlikely. A candidate can win all of the delegates at stake by capturing 85 percent of the vote in a district – a high bar, but one that might be possible for Clinton in some heavily minority state Senate districts.
Alabama
Republicans (50 delegates): Trump has drawn yuge crowds of roughly 30,000 people here twice, has the endorsement of a popular U.S. senator and a less-urban electorate – making it perhaps his best SEC state. Rubio and Cruz are hoping to keep him under 50 percent and siphon away some delegates. Look for Rubio to make a push among more moderate coastal Republicans near Mobile in the First Congressional District. Then again, Trump had one of his massive rallies there in August.
Democrats (53 delegates): Clinton is expected to dominate the Black Belt, a heavily African-American swath across the middle of the state. Much of it is in Rep. Terri Sewell’s Sixth District, and the state’s lone Democrat in Congress has been an active Clinton surrogate. Sanders is hoping for big turnout in college towns like Tuscaloosa and Auburn to mitigate what is likely to be a blowout loss. Fortunately for him, it’s too early for spring football.
Tennessee
Democrats (72 delegates): Clinton is counting on a surge of black votes in Memphis. Sanders can take stock in the fact that the Democratic electorate is whiter here than elsewhere in the South, but there are still old-time conservative Democrats here in addition to liberals. Keep an eye on Blue Dog Democratic Rep. Jim Cooper’s Nashville-based Fifth Congressional District to see if his voters avoid the more liberal option.
Republicans (58 delegates): Rubio is likely to capture urban votes in Nashville and, to a lesser extent, Memphis, to steal away delegates from Trump – who is likely to win statewide, though there has not been as much polling here as in other states. There are heaps of evangelicals for Cruz to cling to, as well.
Arkansas
Republicans (40 delegates): This is one of two Republican races to keep the closest eye on tonight (the other being Cruz’s Alamo) – any of the Big Three could win. Rubio should run strong in Little Rock and the surrounding Second Congressional District. More rural areas would be friendlier to Trump, and further south along the Texas border there is more familiarity with Cruz.
Democrats (32 delegates): The Democratic electorate here is whiter than in some other Southern neighbors, but the Clinton name still goes a long way for the state’s former first lady. Clinton will look to dominate Little Rock, while Sanders can hope to make up ground in college-town Fayetteville and in the rest of the state’s northwest corner.
Oklahoma
Democrats (38 delegates): This is the race to watch tonight on the Democratic side. Polls show it neck and neck, with Sanders making a pair of final week visits here. It is less African-American than the rest of the SEC – 82 percent of the 2008 Democratic primary electorate was white, according to exit polls — and Sanders has seized upon a local issue by going hard against natural gas “fracking” – which is being blamed by environmentalists for a rash of earthquakes in the area. Oklahoma City and Tulsa could be close fights, but Sanders also has opened an office in the college town of Norman.
Republicans (43 delegates): The GOP side of the ballot is also competitive, though a late poll did show Trump up by double digits. The whole state, and particularly the Tulsa area, has a host of evangelicals who could favor Cruz. Rubio has to do well in Oklahoma City to have a shot.
Virginia
Republicans (49 delegates): This is one state where Rubio is looking to sneak up on Trump. Rubio spent considerable time stumping here and on TV ads in the final days. Look for him to do well among well-educated urban moderates in Northern Virginia, the Richmond area and southeastern Virginia. His competition in that space is John Kasich, who has an event Tuesday in Arlington. Trump will do better in the rural areas. One quirk here is that the delegates are awarded proportionally by statewide vote – so no need to keep track of who’s running well in which congressional district.
Democrats (95 delegates): Hillary Clinton can look to dominate in heavily African-American areas around Richmond and the southeastern corner of the state, while Bernie Sanders can do better in the mountain areas. Northern Virginia is a battleground: It’s wealthy, liberal and heavily populated by government workers and contractors. Do they have fond memories of the Clinton years or are they looking to shake things up?
