WASHINGTON, 6 February 2008 — On a sprawling day of coast-to-coast voting — the biggest ever in a US primary race with 43 presidential nominating contests in 24 states — the presidential contenders in both parties fought hard to win a huge cache of delegates to this summer’s nominating conventions.

Political observers say delegate-rich states such as California, New York and New Jersey could be make or break contests for both Republicans and Democrats. But if there’s one state to watch closely, it’s Missouri.

Missouri is one of the nation’s most reliable bellwethers in presidential politics.

For the last century — 1904 to 2004 — it has voted for the winning presidential candidate in every election but one: going for Adlai Stevenson over Dwight Eisenhower in 1956.

The state’s Democratic base is around urban areas such as St. Louis and Kansas City.

Republicans tend to rely on strong support from the more rural central portion of the state, including Springfield and Jefferson City, the state capital.

Strong union support is an important factor for Democrats. Almost four in 10 voters in the 2004 Democratic primary came from a household where someone belonged to a union.

Sixty percent of voters in the 2004 Democratic primary were self-described moderates or conservatives.

Almost a quarter of all voters in the 2000 GOP primary were self-described members of the religious right; 56 percent were self-described conservatives.

One should also consider the youth vote. This year, young voters have registered in record-breaking numbers to take part in the primaries and general elections. Both Sen. Barack Obama and Sen. Hillary Clinton have attracted young voters, who see a chance to help make history.

Hillary, and especially Obama, have captured the imagination of young voters, who recognize their unique chance to put a woman or African-American into the White House.

The youth vote already has played a key role in earlier primaries. In South Carolina, 18- to 29-year-olds accounted for 14 percent of voters, up from 9 percent in 2004. And, in Iowa, young voter turnout rose 135 percent from the previous presidential primary. Obama won both states.

Counting the primary votes is a bit complicated. Democrats allocate most of their delegates proportionately; candidates are awarded a cut of the delegate pie based on their percentage of the vote. It is possible to lose a state and still get a majority of the delegates, and it is likely that the losing candidate will still get a substantial share of the delegates.

But the Republicans’ delegate selection rules are different. In eight of the 21 Republican contests, the winner gets the delegates — no dividing up the spoils.

What that means is that it is going to be easy for a candidate to build up a big delegate lead and, combined with winning some big states, credibly declare himself the party’s presumptive nominee. That is precisely what Sen. John McCain is looking to do.