In a preview of what is being billed as a major economic speech in Detroit later this week, Mitt Romney doubled down on his economic proposals Wednesday.

Standing before a large and boisterous crowd in Chandler, Ariz., Romney promised to make the tax system "simpler, flatter, and fairer," by reducing individual rates by 20 percent across the board. If implemented, the top rate would drop from 35 percent to 28 percent, the same top rate Americans paid under President Reagan in 1986.

To prevent an increase in the federal deficit by lower tax receipts, Romney said he would limit deductions and exemptions for higher-income brackets, saving the burden from falling on the middle class.

"I want to make sure that you understand for middle-income families, the deductibility of home mortgage interest and charitable contributions -- those things will continue," Romney said to loud cheers. "But for high-income folks, we're going to cut back on that, so that we make sure the top 1 percent keeps paying the current share they're paying or more. We want middle-income Americans to be the place we focus our help, because it's middle-income Americans that have been hurt by this Obama economy." (read more)

TUCSON, Ariz. - Rick Santorum took a pre-debate dig at his GOP rival, claiming Mitt Romney's new tax plan looks an awful lot like the one Santorum has already rolled out.

"I just saw today that Governor Romney announced that he was going to be lowering the tax rates to, well, the tax rate I proposed," Santorum quipped during a Tea Party rally in Tucson.

"Welcome to the party, Governor. Great to have you along."

Romney pledged Wednesday to slash tax rates for all Americans by 20% just hours earlier, saying it would not add more debt since he would cap deductions and exemptions for the wealthy.

The proposal could be an attempt to bring renewed focus on the economy, as opposed to the social issues Santorum is connecting with conservatives on.

But the former senator also struck a chord here on illegal immigration. The crowd rose to their feet and erupted with applause after Santorum tied the issue to his own family's history.

"My grandfather came to this country in 1925. He came by himself. He left his family behind, his young children, his wife, he left them after having served in WWI," Santorum explained. (read more)

Two new ads released for broadcast in Michigan Wednesday are hitting Mitt Romney for his opposition to auto-industry bailouts as well as his record on spending.

A sound bite of Romney stating, "Let Detroit go bankrupt," opens the latest ad from Priorities USA Action, a super PAC supporting President Obama.  The ad cites Romney’s record while he was in the private sector of profiting off investments in businesses which later failed.

Romney’s use of the phrase "bankrupt" echoes throughout the ad, as the super PAC hopes it will echo in the minds of voters come Election Day. A Quinnipiac poll, released Wednesday has the Republican presidential primary candidate trailing Obama by 2 points in a head-to-head matchup nationwide.

Michigan is where Romney grew up and the auto bailout affects thousands of people there. A NBC News/Marist poll out on Wednesday shows 63 percent of registered voters in the Great Lakes State back the government's decision to assist General Motors and Chrysler in the fall of 2008, when President George W. Bush was still in office. Forty-two percent of likely voters -- those who would vote in the GOP primary -- back the decision.

The NBC News/Marist poll also shows Obama getting much of the credit for the bailout from registered voters, 58 percent of whom say he gets a great deal or good amount of the props. Among likely voters, only 27 percent give him a great deal or good amount of the credit for the bailout. (read more)

UPDATE 2:00pm ET:  Senate Sergeant at Arms Terrance Gainer has just sent an updated e-mail to all Senate offices confirming that three total congressional offices have received threatening mails containing a powdery substance that has initially tested negative for containing a bio-agent and more letters could be on the way.  

But the Gainer warning, obtained by Fox, makes clear, "The author of these letters has indicated that additional letters containing a powdery substance will be arriving at more Senate offices and that some of these letters may contain an actual harmful material. Although all letters received thus far have proved harmless, it is essential that we treat every piece of suspicious mail as if it may, in fact, be harmful." 

A Senate state office and a House district office received the threatening letters Tuesday, and Gainer says an additional Senate state office received a letter Wednesday.  The Sergeant at Arms does not indicate which office received the correspondence, but Gainer repeats the earlier call for members to be on the lookout for a particular Portland, Oregon address previously reported by Fox. 

Gainer says his staff is "working closely with federal and local law enforcement in this ongoing investigation."

Congressional security officials, police, and staff often work with outside law enforcement. Recently, a joint investigation thwarted a would-be suicide bomber who was intent on attacking the U.S. Capitol.  (read more)

Rick Santorum obliquely referenced reports Tuesday about his 2008 remarks at Ava Maria University in Florida in which he claimed Satan has his "sights" on the U.S. in a battle of good versus evil, and said he won't be distracted from his campaign message.

"You guys, these are questions that are not relevant to what's being discussed in America today. What we're talking about in America today is trying to get America growing. That's what my speeches are about, that's what we're going to talk about in this campaign. If you want to dig up old speeches of talking to a religious group, go right ahead and do so, but I'm gonna stay on message, I'm gonna talk about things that Americans want to talk about which is creating jobs, getting our country safer and secure, and yeah, taking on the forces around this world who want to do harm to America. You bet I'm gonna take them on," he said in a post-speech media scrum in Phoenix.

Fox News' Nick Kalman contributed to this report.

GOP hopeful Newt Gingrich is planning to release a 30-minute long video on gas prices and the economy, a senior adviser to Gingrich told Fox News.

Gingrich quietly shot the video recently in Los Angeles. His campaign hopes the video highlights what they believe is their strength in the race: a long, substantive case against President Obama.

The campaign is planning on buying ad time on local TV stations in key states to air the video. The adviser says the first planned purchase of the video is in Spokane, Washington, where Gingrich has been campaigning heavily in preparation for the state's upcoming caucus.

In the video, Gingrich is seen speaking directly to the camera. He apparently was given a script, but tossed it and spoke off the top of his head.

Gingrich may have referenced the video in an interview with Fox News Channel Tuesday night, where he said he was "gonna find ways to communicate " with the American public.

"I like debates, happens to be good for me, if they're afraid to debate that's fine," he said. "I find other ways to communicate with people with or without their debating." 

Sidelining himself in Arizona and taking a light step in Michigan where Mitt Romney and Rick Santorum are duking it out, Newt Gingrich is honing in on Washington State as the next place where he could notch a win.

Washington holds its non-binding straw poll caucus on March 3. Forty-three delegates are up for grabs –- the most of any contest since the Florida primary and the last one before Super Tuesday.

 “We’ll make a very diligent effort to win the caucus,” campaign spokesman R.C. Hammond said, calling Washington a “pretty big score.”

Gingrich hasn’t announced any public events in Michigan, days after declaring he’d campaign there with the goal of reaching the 15 percent threshold necessary to win delegates. The campaign has also reduced its ambitions in Arizona, with the candidate holding just one public event here after the CNN debate.   (read more)

PHOENIX, Ariz. - Rick Santorum launched a fierce new attack on the national media here for "tearing down" the field of GOP presidential hopefuls.

"Will you be the generation that sat on the sidelines and watched as candidate after candidate comes up and the national media takes their axe out to try to destroy them in every way possible as they've done with every single Republican candidate, and as they will between now and the election?" Santorum asked during a campaign stop in Maricopa County.

He challenged the crowd further, "Will you sit on the sidelines and say boy that's not fair, or will you stand up and fight back for freedom?"

According to an average of the latest polls, Mitt Romney has been ahead in Arizona, but the race is getting tighter with the state's winner-take-all primary now just a week away.

And with 29 delegates up for grabs, Santorum is trying to shore up support by claiming he will be the strongest fighter for the values most important to Arizonans.

"You can speak loudly on Tuesday that you want someone who's going to stand up and fight the insiders, fight the establishment who has a track record of doing it, a track record of cutting spending and taking on the big problems of entitlements. A track record and conviction to fight against the radical Islamists who threaten our country and our freedom," Santorum said. (read more)

The Republican presidential hopefuls, when combined with the Republican National Committee, outraised the total fundraising of President Obama and the DNC in January.

When you add them all together the GOP presidential field and the RNC raised just north of $31.5 million in January of 2012. Meanwhile President Obama's re-election campaign team, when combined with the DNC, raised just under $29.3 million over the same period of time.

It is worth noting that the Super PACs that are supporting the Republican presidential candidates such as, "Winning Our Future" which Backs Newt Gingrich and the pro-Romney group "Restore Our Future," as well as groups supporting Rick Santorum and Ron Paul also raised more than $20 million when combined during the month of January.

The good news for the GOP is the fundraising shows there is enthusiasm out there among Republican voters and activists. However, the bad news is the GOP presidential candidates are spending just about all of their money tearing each other down while President Obama's team saves cash for the general election battle in the fall. (read more)

President Obama will address a meeting of the American Israel Public Affairs Committee (AIPAC) policy conference in early March.

"The president welcomes this opportunity to speak to the strength of the special bonds between Israel and the United States," White House Press Secretary Jay Carney said Tuesday.

Mr. Obama has spoken to the group in the past and this speech comes at amid concerns that Iran will develop a nuclear weapon that would threaten Israel's existence. Defense Secretary Leon Panetta said he believes Israel could launch an attack on Iran this Spring. But the White House said the president's policies have isolated Iran and that sanctions still have time to work.

"[T]he approach this administration has taken has lead to a situation where Iran is isolated as never before, where it is under pressure economically as never before, where there is an international consensus around the idea that ... the problem here is Iranian bad behavior; their refusal to live up to their international obligations," Carney said.

While Iran has claimed its nuclear program is for civilian purposes, it's president Mahmoud Ahmadinejad has also rattled sabers by calling for death to Israel and saying the country will be wiped off the map. (read more)