Although Mr. Bush argued that his plans to deploy interceptor missiles in Poland and a radar station in the Czech Republic were aimed at preventing threats from Iran, Moscow repeatedly said it was aimed against Russia, and has lauded Obama's decision.
Conservatives and security hawks have decried the move as a dangerous capitulation to Russia.
"This decision calls into question the security and diplomatic commitments the United States has made to Poland and the Czech Republic, and has the potential to undermine perceived American leadership in Eastern Europe," Senator McCain said in a statement. "Given the serious and growing threats posed by Iran’s missile and nuclear programs, now is the time when we should look to strengthen our defenses, and those of our allies."
McCain also said the change in US direction is "seriously misguided" and a "victory for [Russian Prime Minister Vladimir] Putin."
Gates answers critics
But it's the critics who are misguided, according to an opinion piece by Defense Secretary Robert Gates that ran in Saturday's New York Times.
Mr. Gates, a Republican who served in senior positions during both Bush presidencies, lashed out at anyone seeking to portray the move as a concession to the Russians.
"I believe this is a very pragmatic proposal. I have found since taking this post that when it comes to missile defense, some hold a view bordering on theology that regards any change of plans or any cancellation of a program as abandonment or even breaking faith," Gates wrote.
"We are strengthening – not scrapping – missile defense in Europe," Gates wrote, noting that the previous program would not have been operational until at least 2017 at the earliest and insisted the shift provided "greater flexibility to adapt as new threats develop and old ones recede."
Under the new plan, the US would initially deploy ships with missile interceptors and later would field land-based defense systems. The change in plans follows a shift in intelligence assessments that concluded that Iran's short- and medium-range missile arsenal is a greater threat than its yet-to-be-developed long-range missiles.
Obama weighs in
President Obama followed up Gates's words by firmly addressing the issue during interviews for the Sunday morning talk shows.
"The Russians don't make determinations about what our defense posture is," Obama told CBS. "If the by-product of it is that the Russians feel a little less paranoid ... then that's a bonus."
"Russia had always been paranoid about this, but George Bush was right. This wasn't a threat to them," Obama said, adding that it would be a bonus if the Russians were "now willing to work more effectively with us to deal with threats like ballistic missiles from Iran or nuclear development in Iran."
Will Russia cooperate on those issues? That's the million-dollar question.
Early indications aren't bad.
Mr. Putin described Obama's decision as "correct and brave." Russia announced this weekend that it would scrap plans to deploy missiles near Poland.
And as Iran's nuclear program again becomes a focus in coming weeks, it should become apparent just how hard a line Russia is willing to take on Iran.
No one should hold his breath, however.
As the Monitor reported last week, the issues are not easily solved.
“It may be that Russia will be more amenable, but this is a deeply complicated issue,” Fyodor Lukyanov, editor of Russia in Global Affairs, a leading Moscow foreign policy journal, told the Monitor. “On Iran, and other regional conflicts, the differences between Moscow and Washington are deep, and that hasn’t changed.”
Meanwhile, critics at home continue to hammer Obama's decision.
"I find it alarming and dangerous that this president has abandoned our friends in Eastern Europe to curry favor with our foes in Russia," 2008 presidential contender Mitt Romney told the Reuters news agency on Sunday.
"This is just the latest chapter in Barack Obama's 'Capitulation & Appeasement Tour 2009.' " screams an editorial in the Pittsburgh Tribune-Review. "Not only has the administration caved to the Russians for nothing in return, it dangerously downplays Iranian capabilities at the exact moment others are ramping up the threat. ... The bottom line is that the United States has made yet another bad decision in pursuit of coddling its enemies and shafting its allies."
– Material from the wires was used in this report.