Early voting by Iowa Democrats, Republicans, and no-party voters already exceeds the number of absentee ballots cast by each of those groups in the 2010 general election. Depending on how many more ballots are returned in time to be counted, this year’s early vote may exceed 40 percent of the electorate.

Democrats lead in absentee ballots returned by about 7,000 statewide but have many more ballots outstanding (about 47,000) than do Republicans (about 30,000). Each 11,000 to 12,000 ballots left on the table represents roughly 1 percent of the expected statewide vote.

Although Senators Tom Harkin and Chuck Grassley have asked the U.S. Postal Service to put legible postmarks on all absentee ballots, I would not risk dropping a ballot in the mail now. If it arrives after election day with no postmark, it will not be counted. Safer to either take your ballot to the post office and demand a postmark on the envelope, or hand-deliver the envelope to the county auditor’s office.

I’ve enclosed below the latest data on absentee ballots requested and returned statewide and in each of Iowa’s four Congressional districts. All figures come from the Iowa Secretary of State’s Office. Click here for previous tables going back to September 22.

The big question remains: which party has mobilized more voters who otherwise would not have participated in the midterm election? A new Des Moines Register analysis suggests Democrats have only a “thin edge” in early voting. But Nate Cohn of the New York Times’ “Upshot” blog has a different take:

In Iowa, the overall early vote is nearly tied in a state where Democrats usually fare well in the early vote.

But Democrats insist that the Republicans are merely banking voters who would have voted on Election Day anyway, and back it up with data showing a lead among people who didn’t vote in 2010, 40 to 29 percent. If the G.O.P. is faring better in the early vote by attracting voters who would have turned out anyway, then they diminish their ability to fare as well on Election Day as they have in the past.

Absentee ballots requested by Iowa voters as of October 30, 2014

Congressional district	Democrats	Republicans	no-party voters	Libertarian	Iowa Green	total
IA-01	55,096	42,192	31,783	155	66	129,292
IA-02	59,640	42,556	30,953	163	95	133,407
IA-03	53,380	47,724	24,249	163	63	125,579
IA-04	39,219	51,625	23,661	103	40	114,648
statewide	207,335	184,097	110,646	584	264	502,926

Absentee ballots received by Iowa county auditors as of October 30, 2014

Congressional district	Democrats	Republicans	no-party voters	Libertarian	Iowa Green	total
IA-01	43,580	35,625	22,905	105	39	102,254
IA-02	46,410	36,395	21,713	109	71	104,698
IA-03	38,928	37,989	15,688	94	37	92,736
IA-04	31,388	43,468	17,135	67	26	92,084
statewide	160,306	153,477	77,441	375	173	391,772