I still have Trump in the 45-50% range for winning re-election. The current state of polls means absolutely nothing to me.
PROS
High approval ratings among Republican voters
Strong/Positive Economy
CONS
Unpopularity
The Democrats hold the advantage when it comes to health-care
To dig deeper here, Presidents/incumbents generally win re-election with high support among their base. When you see a legitimate third party candidate emerging or a serious primary contender, the incumbent/President loses. Just look at George H.W Bush in 1992. When he broke his promise about no new taxes, he alienated his base and gave rise to Ross Perot. With Trump, he seems to be doing everything to please his base, besides promising that Mexico will pay for his wall. We will see if Bill Weld is an actual challenger for Trump. So far Weld is getting no more than 15% in the polls.
On the economic front, things are looking pretty good: Stock market up, GDP has skyrocketed since Trump took office, unemployment rate is at historic lows, poverty is declining, and the average American worker has experience their first pay raise this century. We can debate all day about who's responsible for the positive economic numbers, but at the end of the day, Trump will get credit for it. Historically, we do not change Presidents during a positive economic time period.
Both these elements work in favor of the President, and makes an easy favorite to win re-election.
But on the other hand, there's a lot of evidence to show he's a one-and-done type of President.
For starters, he's wildly unpopular. His approving ratings are in the 42-45% range, and his disapproval ratings are between 52 to 55%. We are basically talking about somebody who is registering at Jimmy Carter and Gerald Ford numbers. In Trump's 2.5 years as President, he's never really went above 45% in the approval side on average, and never been under 50% on the disapproval side on average. That's how bad he is doing. It just so happens in 2016, he was up against a wildly unpopular opponent and banked off the fact that Clinton took the rust belt states for granted and paid little-to-no-attention. As a result, Trump just barely squeaked by in those states. If Clinton won Wisconsin, Michigan, and Penn, she would be President right now.
The second big negative for Trump is health-care. The GOP has yet to put forth a health-care people actually like. Public support for a public option or Medicare-For-All system is extremely high. Even half of Republicans support it. If the Democrats run on the platform of we can fix health-care and improve on ACA, it is going to be a winning issue.