'There's still a dark vein of intolerance in the GOP': Colin Powell says Republican attacks on Obama are 'racist'

 Colin Powell said his party continues to use racially-tainted language against President Barack Obama

Powell maintains he is still a Republican - even though he endorsed Obama for the presidency in both 2008 and 2012. 

'There's also a dark vein of intolerance in some parts of the party,' Powell told 'Meet the Press' host David Gregory. 'What do I mean by that? What I mean by that is they still sort of look down on minorities.'

He cited two instances of racially-charged attacks that bothered him, and he said, other black Americans.

Last fall, former Republican Vice Presidential candidate Sarah Palin said Obama's explanation for the terrorist attacks on the U.S. consulate in Benghazi, Libya, amounted to 'shuck an jive' - term that is often associated with lying behavior among slaves.

Powell also took issue with Republican New Hampshire Gov John Sununu calling Obama 'lazy' after his poor showing at the first presidential debate last fall.

Nominee: Obama's nominee to be the next Secretary of Defense, former Republican Senator Chuck Hagel, has run into some opposition

'He didn't say he was slow, he was tired, he didn't do well; he said he was "lazy,"' Powell said. 'Now, it may not mean anything to most Americans, but to those of us who are African Americans, the second word is "shiftless," and then there's a third word that goes along with it.'

Powell also took aim at the party for its stances on immigration, education and climate change - saying all three would have to change if Republicans hope to win the next presidential election. 

'Everybody wants to talk about, "Who's going to be the candidate?"' Powell said. 'You've got to think first about what's the party actually going to represent?  If it's just going to represent the far right wing of the political spectrum, I think the party is in difficulty. I'm a moderate, but I'm still a Republican.'

He also dismissed the 'birther' movement and said no senior leaders in the Republican party should have ever taken questions about Obama's Hawaiian birth certificate seriously. 

Powell, who was a four star U.S. Army general and chairman of the Joint Chiefs of Staff, also defended Hagel, whose nomination of Secretary of Defense is meeting some resistance in the Senate. 

He said Hagel served bravely as a young soldier in the Vietnam War and will be a firm supporter of the troops.

Hagel has received heat from both Republicans and Democrats for several comments he made while in public office - including a reference to the 'Jewish lobby' that has left some asking whether he is anti-Semitic and worrying about his support for Israel. 

'There are people who are very supportive of the state of Israel,' Powell said. 'I'm very supportive of the state of Israel. So is Senator Hagel, and you'll see that in the confirmation hearings, but it doesn't mean you have to agree with every single position that the Israeli government takes.