Donald Trump is becoming an increasingly serious contender for the 2012 Republican nomination. A new poll from CNN shows him nearly doubling his national support in the past month, moving into a first-place tie with Mike Huckabee.

CNN, 4/9-10, 385 Republicans, MoE 5 (3/11-13 numbers in parenthesis)

Huckabee: 19 (19)

Trump:: 19 (10)

Palin:: 12 (12)

Gingrich:: 11 (14)

Romney:: 11 (18)

Paul:: 7 (8)

Bachmann:: 5 (NA)

Daniels::3 (3)

Pawlenty:: 2 (3)

Santorum:: 2 (3)

Barbour:: * (1)

Someone else (vol):: 3 (4)

None / no one (vol): 4 (3)

No opinion:: 1 (2)

There are big limits to what a national presidential nomination poll can tell us, but this poll is still newsworthy:

Trump's improvement is outside the margin of error;

Trump's improvement comes at the expense of Romney, who is the only Republican to see a decline outside the margin of error;

Trump can perform at levels equal to or better than potential Republican candidates with roughly equal name recognition.

All in all, clownish as the Trump media surge may so far seems, any potential Republican candidate who can improve his numbers at the expense of Mitt Romney can't be dismissed out of hand.

Trump isn't necessarily limiting himself to a run as a Republican, either. He's threatening to run as a third-party candidate if he doesn't win the GOP nomination:

Real estate mogul Donald Trump said Tuesday he could run for president as an Independent if he's unable to win the Republican nomination in 2012. Trump, the reality TV star who has been flirting with a run for president, suggested that other Republicans vying for the party's nomination are concerned he might wage a third-party campaign, which Trump said he thought was a viable path to the White House. "The concern is, if I don't win, will I run as an Independent? And the answer is probably yes," Trump said in a video interview with The Wall Street Journal.

Also in that Wall Street Journal interview, Trump says he will make an announcement on whether he is running "sometime prior to June," and hasn't made an announcement to this point because his television show is airing new episodes.