There's a joke in these parts that if you're wet, you're a Democrat. If you're dry, you're a Republican.

Democrat John Kerry (search) embraced a drenching from the Seattle rain as a baptism into Northwest politics last month. When President Bush arrives in the Pacific Northwest on Thursday night, he'll touch down in the arid landscape around Spokane, the largest city in conservative eastern Washington.

No Republican presidential candidate since Ronald Reagan (search) has carried the Northwest, where the big population centers around Portland and Seattle — known almost as much for their liberal politics as for their incessant drizzle — tend to overrule conservative voters in the smaller towns and cities east of the Cascade Mountains.

But there are signs the wet-dry rule doesn't work as well as it once did. Both Bush and Kerry are working both sides of the region for votes. Democrat Al Gore (search) carried Oregon by a whisker four years ago, and the 5 percentage points of cushion he had in Washington aren't enough to douse Republican hopes of taking the state. Meanwhile, a third-party challenge from Ralph Nader (search) could siphon off enough Democratic votes to put the two states in play.

"On the west side of the mountains in both states, people are pretty liberal on a variety of issues, particularly on the war, with peace activists who have been vocally upset with the president on the war," said James Thurber, a political scientist with Northwest roots who directs the Center for Congressional and Presidential Studies at American University in Washington, D.C.

"The very few people who live in the rest of the states, two-thirds of the territory perhaps, are pretty conservative, but they will not make the difference. It is those who live in the suburbs and the independents, the undecideds, who will determine how tight it is in the Northwest," Thurber said.

With a record-busting war chest, Bush is advertising relentlessly to those — let's call them moist — swing voters, pounding Kerry on taxes and his ambivalent voting record on the Iraq war. If nothing else, the onslaught has had the effect of forcing Kerry — who's also loaded with campaign cash — to respond in kind.

"Quite simply, Washington and Oregon are in play because Bush is spending money here," said Stuart Elway, an independent pollster based in Seattle. "It's hard to imagine them contesting Washington so closely if Bush had less money. They'd be focused in Ohio and Missouri and Pennsylvania and wouldn't be spending so much on their tactical ground game here."

Recent polls show Kerry with a slight lead in both Oregon and Washington.

Kerry's campaign hopes to capitalize on the hard times that have befallen the Northwest since 2000, along with pro-business Bush environmental policies that play better in the sparsely populated dry areas than among the green-leaning voters of the western region.

Unemployment is among the highest in the nation — 6.1 percent in Washington, 6.8 percent in Oregon — driven down by the implosion of the high-tech boom and tens of thousands of post-Sept. 11 layoffs at Boeing airplane plants.

But exactly where voters will place blame for the hard times isn't clear. Although much of the high-tech community is solidly in the Democrats' camp, Bush has drawn support from some prominent executives at high-tech companies including Microsoft, which President Clinton's Justice Department targeted. Meanwhile, Boeing just landed a $3.89 billion contract to build airplanes for the Navy.

"The Pacific Northwest is one of the few places where the Bush campaign can go and take states away from the Democrats," state Republican Party Chairman Chris Vance said, although he concedes that just provoking Kerry into campaigning here was a victory. "Democrats don't want to have to compete here."

Vance's counterpart, Democratic Party Chairman Paul Berendt, dismisses Bush's appeal here and sees more of a threat from the left, where a challenge from Nader — who won 4 percent of the vote in Washington and 5 percent in Oregon four years ago — might peel off enough hard-core environmentalists and peace activists to give Kerry problems.

"We're not hemorrhaging on the right but on the left," Berendt said. "The moderates in this state hate the Bush administration and everything it stands for."