Ted Cruz
Republican presidential candidate Sen. Ted Cruz (R-TX) speaks to crowd during a campaign rally at Ottawa Farms December 19, 2015 in Bloomingdale, Georgia. This stop on the 'Take off with Ted Cruz Country Christmas Tour' featured one of the largest crowds of his tour so far at one of the last cattle farms in the county. Nicholas Pilch/Getty Images

A new poll released by CBS News/YouGov on 20 December revealed that while Republican presidential candidate Donald Trump remains a frontrunner in his party, Texas Senator Ted Cruz has gained the lead in Iowa. Trump does, however, maintain the lead in two key states: New Hampshire and South Carolina.

Iowa

Cruz holds a slight leadover Trump in Iowa with 40% of Republican likely caucus voter support over Trump's 31%. The two are followed not-so-closely behind by Florida Senator Marco Rubio with 12% and retired neurosurgeon Ben Carson with 6%. The remaining candidates all earned 2% or less in Iowa. CBS News credits Cruz's jump to support from evangelical voters and those formerly supporting Carson.

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In the Democratic side, former Secretary of State Hillary Clinton and Vermont Senator Bernie Sanders both have substantial support from Democratic likely caucus voters. Clinton maintains the lead with 50%, but Sanders is close behind with 45%. Meanwhile, former Maryland Governor Martin O'Malley only manages 4% support.

New Hampshire

Trump managed a large lead in New Hampshire, where he received 32% support from Republican likely primary voters. Cruz grabbed second place with 14% and was followed closely behind by Rubio with 13%. New Jersey Governor Chris Christie, who has spent a considerable time in New Hampshire during his campaign, came in fourth with 11%. Ohio Governor John Kasich rounds up the top five with 8%, while the remaining candidates garnered 6% or less.

Unlike in Iowa, Clinton does not hold the lead in New Hampshire. The former First Lady trails Sanders 42% to his 56%. O'Malley faired even worse in The Granite State with only 1%.

South Carolina

In South Carolina, Trump also held on to the lead with 38%, with Cruz hot on his trail at 23%. Rubio was again in third place with 12% and Carson was fourth with 9%. Former Florida Governor Jeb Bush, who was once favoured to get the party's nomination held fifth position with 7%.

Clinton holds her biggest lead in South Carolina, with 67% of the vote. Sanders was not-so-closely behind with 31%, while O'Malley managed only 2%.

The new poll revealed that voters in all three key states believe the US is more dangerous and insecure country — 75% in Iowa, 70% in New Hampshire and 73% in South Carolina. Less than 10% in the three states believe the country is becoming a safer and more secure country. Voters also were less optimistic about the American economy, with over 60% believing the country's economy is moving towards a system that makes things harder for them.

According to CBS News, the poll was conducted between 13-17 December through 3,812 interviews with voters in Iowa, New Hampshire and South Carolina. The poll was conducted for CBS News by YouGov.

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Ted Cruz Donald Trump Bernie Sanders Hillary Clinton