The steep increase comes most sharply among Democrats, though there are increases across party lines. Back in January, just 23% of Democrats called it a crisis as President Donald Trump took that line in an effort to build support for border wall funding during the longest-ever government shutdown. Now, 70% of Democrats see the situation at the border as a crisis.

Among independents, the share who see a crisis at the border has climbed from 47% to 72%, and among Republicans, it's up 11 points to 82%.

The same poll finds little movement in Trump's approval rating over that time for handling immigration (42% approve now, 41% did in January). Trump's overall approval numbers hold steady in the new poll at 43% approving and 52% disapproving.

There is disagreement across party lines about the cause of the crisis at the border. A majority of Democrats consider it a crisis because of the treatment migrants are receiving as they attempt to cross the border (54%), while most Republicans say they think it's a crisis because of the number of migrants attempting to enter the country (63%). Among independents, slightly more say it's a crisis due to the number of migrants attempting to cross (35%) than because of the treatment migrants are receiving (28%).

About 6 in 10 Americans (62%) say they disapprove of the treatment migrants are receiving at the border, but there's a steep partisan divide here as well. Democrats are near-unanimous in their disapproval (93% disapprove), and a majority of independents feel the same (60%), but most Republicans (62%) say they approve of the way migrants are being treated by the government after crossing the US-Mexico border.

There is a similarly large partisan divide over whether refugees from Central American countries should be able to seek asylum in the US. While a majority of Americans (60%) say yes, that stands at 85% among Democrats, 60% among independents and just 31% among Republicans.

But majorities across party lines say that the government's top priority in dealing with immigrants living in the US illegally ought to be developing a plan to allow some people doing so to become legal residents (80% overall say so, including 96% of Democrats, 81% of independents and 63% of Republicans).

Just 15% overall -- and only 32% of Republicans -- say the nation should prioritize deporting all people living in the US illegally over developing such a plan.

The survey also finds little movement in approval ratings for the President's handling of foreign affairs generally (40% approve, 54% disapprove, neither changed significantly since April).

But there have been increases in disapproval for the President's handling of North Korea (49% disapprove, up from 45% in May and the highest disapproval in more than a year) and Iran (51% disapprove, up from 43% in May). The poll was in the field when the President became the first American president to set foot in North Korea, and found no difference in approval ratings on this issue measured after that event.

Democratic disapproval of the President's handling of both North Korea and Iran has grown in the last month (from 77% to 85% disapproval on North Korea, and from 71% to 89% on Iran), while Republican approval has also ticked up from 66% to 75% on his handling of Iran and from 73% to 78% on North Korea.

Americans continue to say things in the US generally are going well (57% say so, about the same as last November), with 42% saying things are going badly.

Trump's steadily negative approval ratings come alongside steadily negative favorability ratings.

Overall, 41% have a favorable view of the President and 56% an unfavorable one. That is a bit more negative than in May or April, but about the same as his standing in March.

Among registered voters, the 12-point deficit Trump faces in favorability ratings is larger than those faced by any of the Democrats attempting to unseat him in 2020 who were tested in this poll. The worst-rated Democrat in the poll -- Vermont Sen. Bernie Sanders, according to results from the same poll released on Monday -- holds a net-negative rating among registered voters by 6 points.

The CNN Poll was conducted by SSRS Friday through Sunday among a random national sample of 1,613 adults reached on landlines or cellphones by a live interviewer. Results for the full sample have a margin of sampling error of plus or minus 3.0 percentage points. It is larger for subgroups.