Aug. 30 (Bloomberg) -- Former Senator Fred Thompson, after months of flirting with a possible presidential run, will enter the 2008 Republican nomination contest next week with a Sept. 6 Internet announcement and five-day campaign tour through Iowa, New Hampshire and South Carolina, his organization said today.

The former Tennessee senator, lawyer and lobbyist, who has had a parallel career as a Hollywood movie and television actor, will become the ninth Republican candidate. He consistently ranks among the top three contenders in polls of Republican voters, behind former New York Mayor Rudy Giuliani and ahead of or even with former Massachusetts Governor Mitt Romney.

``We enter this campaign in a strong position,'' Bill Lacy, the manager of Thompson's exploratory committee, said in a statement released after a conference call with supporters. ``Conservatives across the country have put together the closest thing to a draft in recent presidential campaign history.''

Thompson has drawn interest because he is making his pitch to Southerners and members of the Republican Party who consider a candidate's views on abortion, same-sex marriage and religion as defining issues. The key is whether he can sustain that interest through the primaries and caucuses that will decide the nomination.

Window of Opportunity

``From the moment that Thompson declares, he has about a one- week window for people to say he's for real or not,'' former White House spokesman Ari Fleischer said last week. ``If people get a let-down feeling after his announcement, because he got in so late, it will be harder for him to recover.''

The tour he plans after the announcement will take him to three of the first states holding contests for the nomination. His formal declaration will enable Thompson to begin campaigning in earnest. An undeclared presidential hopeful is prohibited from running commercials or otherwise acting like a candidate.

``He's a bit hamstrung right now,'' said Federal Election Commission spokesman Bob Biersack. ``He can't advertise. He can't say `vote for me.'''

Being able to fully campaign may help boost donations. In June, Thompson's exploratory committee took in $3.46 million from two fundraisers and donors over the Internet. ``A wonderful month by any measure,'' Thompson said in an Aug. 28 interview.

Since then, contributions have slowed. Thompson said that ``September would be great'' for fundraising.

Voting Record

Thompson, who served eight years as a Tennessee senator before deciding not to seek re-election in 2002, has been touting his conservative credentials. He says he's ``unabashedly'' against allowing abortion and is a strong supporter of the Second Amendment right to bear arms.

``You look at my voting record on things like taxes, regulations, national security, abortion-related issues and guns,'' Thompson, 65, said in the interview. ``By any measure, I've got a conservative voting record and I think those are the principles our country was founded and that's what makes for a better nation.''

Thompson has already criticized Republican frontrunner Giuliani's stance on gun control, citing legal efforts Giuliani attempted to target gunmakers.

He also takes a hard-line stance against illegal immigration and was highly critical of the failed effort in Congress to overhaul the law. He links it to national security.

Border Security

``We can't or won't stop illegal immigrants from coming across our borders when in the last few years we've picked up thousands of people from terror-related states alone,'' he said in an Aug. 25 speech before the Midwest Republican Leadership Conference in Indianapolis. ``We only catch one out of three in the era of the suitcase bomb, where a small amount of material could wreak havoc on this country.''

His pending candidacy has hurt John McCain by knocking the Arizona senator out of the top three in most national polls.

In an Aug. 21-22 nationwide Fox News survey of Republican voters, Giuliani led with 29 percent, followed by Thompson with 14 percent and Romney with 11 percent. McCain, who started the year as the Republican frontrunner, drew 7 percent.

Thompson disclosed in April that he was diagnosed more than two years ago with indolent lymphoma and that the disease is in remission. Lymphoma is a cancer of a part of the immune system called the lymphatic system.

The disease begins when certain types of infection-fighting cells become abnormal and start dividing, producing more and more abnormal cells that can spread throughout the body. Patients with slow-growing lymphoma can live with the disease 20 years or more.

To contact the reporter on this story: Kim Chipman in Washington at kchipman@Bloomberg.net.

Last Updated: August 30, 2007 18:55 EDT