As voters in two states indicate their preference Tuesday in the Republican race for President, Mitt Romney's final serious challenger has all but suspended his campaign, as Ron Paul says he will not actively campaign in any of the primaries remaining in this year's GOP race.

Paul told his backers in an email that he simply didn't have the money to go forward.

"Doing so with any hope of success would take many tens of millions of dollars we simply do not have," Paul wrote.

Paul wasn't expected to make much of a showing on Tuesday, as 25 delegates are at stake in Oregon, but none are up for grabs in Nebraska - as the Cornhusker State voting is just a non-binding beauty contest.

Mitt Romney made a campaign stop in Nebraska last week, but during Tuesday's voting the GOP frontrunner will be in Iowa, giving a speech on the budget deficit at Drake University.

Oregon does not pick the actual delegates until June 23, while Nebraska has its GOP convention on July 14.

Those Republican gatherings - and more like them in coming weeks - will again give Paul forces the chance to grab delegate slots to the national Republican convention, even if they are bound to Romney on the first ballot.

The delegate selection must go according to the primary results in Oregon, meaning Paul has the best chance to pick up delegates in the Cornhusker State, just as he did in Maine a few weekends ago.

The Associates Press delegate count at this point gives Mitt Romney 966 of the 1144 he needs to claim the GOP nomiation.

In terms of races for Congress in Oregon and Nebraska, probably the closest attention will be paid to the primaries for U.S. Senate in Nebraska, where candidates are trying to succeed the retiring Sen. Ben Nelson (D-NE).

The big name on the Democratic side is former Sen. Bob Kerrey of Nebraska, who is trying to regain his past job. The GOP favorite is state Attorney General Jon Bruning, but polls indicate that Republican race is close.