WASHINGTON – National Republican and Democratic groups are shifting their attention – and money – away from Maine’s U.S. Senate campaign to focus on more competitive races across the country.

After funneling more than $6 million into Maine in recent months, out-of-state groups appear to be walking away or dramatically scaling back their involvement in the Senate race as Republicans’ hopes of retaining the seat fade.

The shift signals that independent Angus King continues to enjoy a comfortable lead in the race to replace retiring Republican Sen. Olympia Snowe.

“With a week left, they are being forced to make decisions about where they are investing, so Maine does not look like the best investment anymore,” said Nathan Gonzales, deputy editor with The Rothenberg Political Report, a closely watched, nonpartisan campaign analysis newsletter in Washington.

The National Republican Senatorial Committee, which has spent more than $1.3 million opposing King, has not bought any new airtime on WGME-TV in Portland since Oct. 18, or on WCSH in Portland and WLBZ in Bangor since Oct. 16.

The U.S. Chamber of Commerce – another big spender against King and for Republican Charlie Summers – has not aired any ads since Oct. 22, according to public filings with the stations.

The Democratic Senatorial Campaign Committee canceled all anti-Summers ads on WCSH after Tuesday and scrapped a large portion of its purchase on WGME. The committee, which has not endorsed Democratic nominee Cynthia Dill and appears to be implicitly backing King, kept some ad time reserved on WGME through Election Day, records show.

The groups’ departure suggests that national Republican leaders are no longer confident that Summers can close the gap against King, who has led in the polls since he joined the race in March.

Less than nine months ago, the seat was considered a sure bet for Republicans thanks to Snowe’s popularity among Maine’s moderate electorate. Her surprise announcement in February that she would retire thrust the race into the national spotlight.

King has refused to say which party he would caucus with in the Senate, but Republican and Democratic leaders in Washington say he will likely side with the Democrats.

The Summers and King campaigns declined to comment on the advertising decisions by the outside groups. Federal election law prohibits campaigns from coordinating with independent political action committees and politically engaged nonprofits like the U.S. Chamber of Commerce.

Summers spokesman Drew Brandewie, speaking late last week, when anonymous reports began circulating about the shift, indicated that Summers would campaign as usual.

“Charlie is going to continue to travel across the state and continue to talk to the blue-collar workers … about his plans for cutting taxes, ending deficit spending and easing the regulatory burden on businesses,” Brandewie said.

Representatives from the National Republican Senatorial Committee and the Democratic Senatorial Campaign Committee did not respond to requests for comment.

Extensive internal polling and advanced computer-based tools enable campaigns and outside groups to change strategies quickly. And where independent groups and national parties spend money in the latter days of a campaign offers a glimpse into what those closely guarded internal polls are saying.

Federal Election Commission reports on independent expenditures typically lag several days behind what is actually happening. But recent reports to the FEC strongly suggest that Maine’s Senate race is attracting fewer dollars from national groups.

Outside groups spent or committed an additional $1.1 million for Maine’s Senate race from Oct. 23 to 29, according to FEC data. That brought total outside spending on the race to nearly $7 million.

In Virginia, outside groups dumped another $12 million into that state’s contentious Senate race and an additional $8 million into Wisconsin’s race during that period.

Gonzales, with The Rothenberg Political Report, said organizations may invest that money in new places – such as the tightening Senate race in Pennsylvania – or use it to bolster their campaigns in battleground states.

He said Republicans’ loss of Snowe’s seat in Maine would likely be offset by Democrats’ loss of a seat in Nebraska, where Democratic Sen. Ben Nelson is retiring. But like other observers, Gonzales said Republicans may have a tougher time winning control of the Senate than envisioned a few months ago.

“I think Democrats are certainly more likely to hold on to a majority than Republicans are in taking it over,” he said.

Not every outside group appears to be withdrawing from Maine. Americans Elect, a nonprofit supporting King, has not canceled any of its reserved spots through Nov. 5, spokeswoman Ileana Wachtel said Monday.

The Republican group Crossroads GPS was still airing anti-King ads on Monday, although that run may end on Tuesday.

Staff Writer John Richardson contributed to this report.

Washington Bureau Chief Kevin Miller can be contacted at 317-6256 or at:

kmiller@mainetoday.com

Twitter: @KevinMillerDC