This is a summary of the current probabilities of various combinations of events implicitly assigned by the Iowa Electronic Markets real-money political futures markets. See the prospectus for each market for further details. Also see the notes below.

The state-by-state markets run by TradeSports.com of Dublin, Ireland, may also be of interest. A nice map presentation of the current TradeSports quotes is available at geekmedia.org.

2004 Presidential two-party vote outcomes:

Republican nominee wins the two-party popular vote: pro 99.1-99.2% contra 0.8-0.9%
Republican nominee by 52-100% of the two-party popular vote: pro 0.6-0.7% contra 99.3-99.4%
Republican nominee by 50-52% of the two-party popular vote: pro 98.4-98.5% contra 1.5-1.6%
Democrat nominee by 50-52% of the two-party popular vote: pro 0.0-0.1% contra 99.9-100.0%
Democrat nominee by 52-100% of the two-party popular vote: pro 0.7-0.8% contra 99.2-99.3%
Winning two-party nominee has 52-100% of the two-party popular vote: pro 1.4-1.5% contra 98.5-98.6%
Republican by 52-100% or Democrat by 50-52%: pro 0.7-0.8% contra 99.2-99.3%

2004 Presidential two-party vote share expectations:

Republican nominee share of the two-party popular vote: 51.4-51.5%

2004 Congressional election outcomes:

Republicans retain House majority (218-435 seats): pro 99.7-100.0% contra 0.0-0.3%
Republicans retain Senate majority (51-100 seats): pro 99.7-100.0% contra 0.0-0.3%
Republican majority in House and Senate: pro 99.7-100.0% contra 0.0-0.3%
Republican majority in House, not in Senate: pro 0.0-0.2% contra 99.8-100.0%
Republican majority in Senate, not in House: pro 0.0-0.1% contra 99.9-100.0%
No Republican majority in House or Senate: pro 0.0-0.3% contra 99.7-100.0%
Split houses (Rep. majority in one, not in other): pro 0.0-0.3% contra 99.7-100.0%

2004 House election outcomes:

Republicans strengthen House majority (229-435 seats): pro 98.9-99.9% contra 0.1-1.1%
Republicans hold majority without gaining (218-228 seats): pro 0.0-0.1% contra 99.9-100.0%
Republicans lose majority (0-217 seats): pro 0.1-1.0% contra 99.0-99.9%

2004 Senate election outcomes:

Republicans strengthen Senate majority (52-100 seats): pro 99.8-99.9% contra 0.1-0.2%
Republicans hold majority without gaining (51 seats): pro 0.0-0.1% contra 99.9-100.0%
Republicans lose majority (0-50 seats): pro 0.0-0.1% contra 99.9-100.0%

Notes

If you believe that the probability of some outcome (or expectation of some variable) is outside the range given above, at this moment you can execute a combination of trades in the Iowa Electronic Markets that on your belief has positive expected profit (once all contracts are liquidated).

If some outcome (or expectation) is in an unstable state (the range given is reversed), at this moment you can execute a combination of trades that is guaranteed to yield an immediate profit.

Note that frequently market prices place tighter bounds on a combination of events than could be inferred from the bounds on the individual events.

Some outcomes are logically equivalent to those listed in another market. I did not bother to figure out how to use trades in multiple markets to place tighter bounds on the common outcomes.

Quotes obtained Thu Nov 4 08:45:55 EST 2004.