The solution consists of several parts.
- First of all, you do not need to guard your daughter from extreme political Views. Views are not facts. They are opinions. Moreover, preventing her from being able to know that there are diversity of views is more likely to turn her into one of those hyper-polarized political people who wish people death just for being a conservative.
Explain to your daughter that everyone has opinions. Some are more backed up by facts than others. Some are more popular than others. Give examples of opposing opinions (not necessarily political).
Explain that she is not required to believe any specific person's opinions, even her Grandmother (or, to balance the political concern, her public school teachers who will teach her that Obama is the greatest and Romney sucks - example from HuffPost to avoid right wing sources :). Another Example with Romney. Another example. And another). Or college professors. My own kids' kindergarten teacher gave them (at age 5) a lecture on how Government is Great and Does Everything for Us.
Explain the difference between respecting a person and respecting their opinion.
Second, explain that FACTS rule. If someone has an opinion, her first duty is to verify if the opinion is backed up by facts.
If someone says that 2000+ cases are the fault of Obama, do you have clear proof that they are not? Show her the proof. BAM. The person stating the opinion lost more than if they not spoke at all.
Of course, conversely, if you don't have any proof that they are NOT the fault of Obama, you should refrain from phrasing an opinion that they are not (or at least pushing that opinion as more valid than that of her grandmother). Explain that the correct answer is "We don't know because there's no evidence either way".
Use the political points as excellent jumping point for education.
Grandma says "Obama is Socialist"? Fine, explain to her exactly what socialism is, what communism and capitalism is. Explain WHY some people consider Obama Socialist (poor definition knowledge? Very close familiarity with Socialism AND with Obamas lifelong views? Imprecise wording/sloppy labeling? Effective political tactics?)
- Apply the same to her Grandmother. Make it a rule - don't propose a political opinion without either honestly admitting it's an opinion OR backing it up with facts.