(Des Moines Register) -- A week after he quit the presidential race, fundraising mailers from Rick Santorum arrived in Iowa mailboxes Monday with a strongly-worded warning.
"It truly frightens me to think what'll happen if Mitt Romney is the nominee," says the letter signed by Santorum and paid for by his campaign.
The undated letter says there's still time for conservatives to make sure the GOP doesn't nominate "a Massachusetts Moderate" and that Republicans would be "crippled" if Romney were to become the nominee.
The blunt message quickly had Republicans here speculating: Did Santorum order up the mailer right before he suspended his campaign on April 10, so its timing was just a simple and understandable mistake? Or, did Santorum, who is still raising money and possibly not quite ready to come to grips with his loss, send this wording out deliberately?
The mailers were paid for and sent before Santorum stepped out of the race, Santorum campaign spokeswoman Alice Stewart said tonight.
Read the letter
Earlier in the day, conservative radio talk show host Steve Deace said he thought there were four possible explanations.
"One, this is simple campaign ineptitude. Two, there is conflict between Santorum's personal convictions and those within his campaign who would like their careers extended by Romney come the general election," Deace said.
Deace noted that a top Santorum adviser last week insisted he would campaign with Romney, and that major financial backer Foster Friess has already shifted his support to Romney.
But last night, Santorum declined to endorse Romney during a conference call with supporters meant to offer thanks and to ask for money.
"Three, this is simply an attempt to leverage more out of Romney by reminding him his base likes him less than they liked McCain, and four, all of the above," said Deace, whose show airs on KTIA 99.3 FM in Boone, WHO 1040 AM in Des Moines, KMA 960 AM in Shenandoah, and stations in several other states.
Steve Grubbs, a GOP strategist from Davenport who was Iowa campaign chairman for presidential candidate Herman Cain, said: "I'm sure the Santorum campaign is regretting that mail piece at this point, because as much as they may not have wanted to lose to Romney, I'm sure they don't want to be seen as hurting the chances for the GOP this fall."
Grubbs said national direct mail is tricky for campaigns because it can take half a month to be delivered.
"Well after Herman Cain dropped out, we had mail landing telling people we were on the verge of winning the nomination," Grubbs said.
He added that late mailers are a double mistake for campaigns because they send a negative message after the time for that has come and gone - and they cost thousands of dollars and return almost nothing in contributions.
Santorum expressed fondness for Iowa in his speech withdrawing from the race last week, saying his victory in the Iowa caucuses gave an improbable candidate a big boost. Romney nearly tied him in the caucuses, finishing within a historically close margin of 34 votes.
In the fundraising letter that arrived in Iowa, Santorum said Republicans would be "crippled" if Romney were the one chosen to take on President Barack Obama.
"My friend, Republicans and conservatives will be crippled by a nominee who presents zero contrast with Barack Obama on the major issues of this election," Santorum wrote. "Any attempt by Mitt Romney to attack President Obama's positions on health-care, energy policy, social issues, or the economy will be easily neutralized."
Romney is widely considered the GOP nominee at this point, although that will officially be decided at the Republican national convention in Tampa in late August.