WASHINGTON -- Democrat Sheldon Whitehouse continues to lead the Senate pack in campaign fundraising, increasing the likelihood that he will take a big cash advantage into the fall contest against the winner of Rhode Island's Republican primary.

The latest federal reports also show that Sen. Lincoln D. Chafee has far outspent Cranston Mayor Stephen P. Laffey -- $2.85 million to $1.18 million -- on the toughest primary challenge a Rhode Island senator has ever faced.

But Laffey still had about $626,000 in cash on hand for the crucial home stretch run to the Sept. 12 primary, while Chafee's primary account was down to about $442,000.

The figures came from reports filed this week with the Federal Election Commission, covering the period from July 1 to Aug. 23.

Laffey raised $280,626 between July 1 and Aug. 23 -- about $25,000 more than Chafee -- putting himself on track to log his fifth consecutive fundraising quarter of more than $300,000.

Laffey has thus avoided a common pitfall for challengers in high-stakes races: a fast start at raising and spending money, followed by declining income and low cash reserves in the all-important closing weeks of the campaign. Such a pattern led Democratic Senate candidate Matthew Brown to controversial fundraising practices and an early departure from the primary race against Whitehouse.

The absence of a well-heeled rival has been a boon to the Whitehouse campaign. He has rivaled Chafee in total spending of $2.6 million -- much of it on TV advertising to introduce himself to voters on his own terms and to attack Republican policies. Unlike Chafee and Laffey, Whitehouse has sustained no advertising attacks from freespending outside groups.

Whitehouse still had $1.53 million in the bank on Aug. 23, with no need for a blitz of spending in the final days before the primary. Another Democratic candidate, businessman Carl Sheeler, reported that he raised $42,055 during the period (July 1 to Aug. 23) and had about $292,000 in cash left on hand. Democratic candidate Christopher Young, who is also running for mayor of Providence, has not raised enough money to file FEC reports.

Chafee had a total of $846,260 in cash on hand for the primary and general elections; Laffey had $856,607 left. But presumably, both will spend heavily until Sept. 12, leaving them further behind Whitehouse -- should he win his Democratic primary.

The financial problem could be more acute for Laffey, if he wins the GOP primary, than for Chafee. Chafee has made clear that if he survives to the general election, he will reach as deeply as he needs into a family fortune worth tens of millions of dollars.

Furthermore, the public polls so far have showed Chafee in a stronger position than Laffey to hold the seat for the GOP. If Chafee wins the primary he might therefore be seen as a better investment for national Republican contributors. If Laffey is the GOP candidate, he might need to show polling gains against the Democrat in order to attract heavy support from national Republicans.

The self-made Laffey is worth several million dollars; he has not made clear how much of his own money he might spend on a general election race.

Laffey has shown sustained appeal to a part of the national Republican base of campaign contributors, notably the members of the Club for Growth, which advocates lower federal taxes.

But as Laffey has often pointed out on the stump, the White House, the Senate Republican campaign organization and other elements of the GOP establishment have been pouring money into Chafee's campaign. It is not clear whether such sources would rush to help Laffey in a general election campaign.

With reports by Journal Staff Writer Scott MacKay

jmulligan@belo-dc.com / (202) 661-8423