Fresh off of its high-profile battle with the White House in the Pennsylvania Senate GOP primary, the conservative group Club for Growth is set to launch an advertising campaign in battleground states lauding President Bush’s economic and security policies.

The club will announce the details of its $500,000 soft-money ad buy today at the National Press Club. According to a release, the campaign will have a “September 11 theme” and will support the Bush administration’s actions since that day. The spot is scheduled to begin airing May 14.

While the Club for Growth has already gotten involved in several Congressional races this cycle, the group’s most visible effort came on behalf of Rep. Pat Toomey in his bid to unseat Sen. Arlen Specter in last month’s Pennsylvania Republican Senate primary.

Toomey lost narrowly after President Bush and several administration surrogates weighed in heavily on behalf of Specter. While the club and some other conservative groups described the incumbent as insufficiently loyal to the GOP, the White House and other Specter backers warned that a Toomey primary victory could lead to the party’s losing the seat in November.

“The timing with the Pennsylvania primary is purely coincidental,” said David Keating, the club’s executive director. “We’re not trying to curry favor with the White House. We’re trying to defend good policies coming out of the White House.”

Since campaign finance reform took effect following the 2002 elections, several outside groups — a so-called de facto “shadow Democratic Party” — have joined forces to raise and spend millions of dollars in soft money to promote liberal causes and the defeat of Bush.

Soft money in support of Bush and the GOP has been less in evidence, but the Club for Growth operates both hard- and soft-money committees and is positioned to do more in the near future if it chooses.

Citizens United, another conservative group which is run by former House GOP aide David Bossie, also plans to start running $100,000 worth of pro-Bush ads this week.