The recent raft of stories about shifts and increases in voter registration in Oregon – especially the pickup in Democratic numbers – have tended to look at the short run of the last three or four months. Which has generated some interesting stats, but we thought we’d take a little longer look – the numbers from March 2007 compared to March 2008.

The Oregonian reported a couple of days ago, for example, that “Oregon Democrats, who began the year with about 70,000 more registered voters than Republicans, have doubled that advantage, which stood Friday at 826,984 Democrats to 685,344 Republicans.”

So what over the course of a year?

In March 2007, Democratic registrants in Oregon totaled 767,214, and Republicans 703,564 – a gap of somewhat over 63,000. In March 2008: Democrats, 803,042 (a gain of around 35,000), and Republicans 685,469 – a loss of about 18,000. Two points: A Democratic gain has been underway for an extended period, throughout the last year; but about 22,000 voters of it – a big portion – has emerged in just the last few weeks. (But might some of those be primary election switchers? The March-March count comparison does control for that to a degree.)

As of the Secretary of State’s March reports, Democrats are in the majority in Benton, Clackamas, Clatsop, Columbia, Coos, Hood River, Lane, Lincoln, Multnomah (approaching 3-1 there), Tillamook, Wasco, and Washington. In March 2007, Clackamas and Washington were majority Republican.

Even in the smaller counties, you see some fallout. Baker County Democrats went from 3,009 to 3,013, and Republicans fell from 4,809 to 4,749 – down 60, in a county with fewer than 8,000 voters and very little Democratic official presence. (In Multnomah County, Republicans lost about 4,000 registrants.)

Another point worth making: The number of non-affiliateds dropped from March to March, from 441,491 to 431,773 – about 10,000.

One more thing. Oregon’s most heated major contest this year looks to be the U.S. House race in District 5, and the party registration shifts may have something to say about that. Not much noted so far has been the shift in registration in the 5th, which usually has been described as a very close or maybe Republican-leaning district (and understandably, when you see that most of the legislators there are Republican).

However. In March 2007, Democrats there numbered 143,301, and Republicans 149,474. Last month, Democrats totaled 149,377 and Republicans 145,692 – a gain of about 6,000 and a loss of about 4,000, respectively, and a switch in preference. (Non-affiliated lost about 5,000 in the 5th.) That could be enough to make a difference in an otherwise close race, as this one prospectively could be.