Approval Ratings Are Key
Senators are not free actors. They need to be re-elected. Their calculation on whether to oppose a Republican president will depend heavily (if not entirely) on whether the president will help or hurt them in their re-election bids. That depends on the president’s approval ratings, particularly in the senators’ home states.
According to a Fox News poll taken just before Inauguration Day, 37% of those polled approved of Trump’s performance and 54% did not. And therein lies Trump’s problem and battleground.
President George W. Bush, President Richard Nixon, President Lyndon B. Johnson, and President Harry S. Truman all had approval ratings around 37% toward the end of their terms. This number is normal for a failed or worn-out presidency.
I know of no president in the 20th century who began his term this way. Each party historically commands about 40% support among voters. When a president falls below 40%, he is actually losing support from his own party. It is normally hard to come back from that… and it usually takes years to get to that low level.
This poses a problem for Trump’s administration. With these numbers, it is possible that more than three Republican senators could decide that rigid support for the president might cost them their political lives.
Trump’s approval ratings are unlikely to fall below 37%, but to be effective, he can’t stay at that level. Republican senators will look at the president’s negative ratings in their states and calculate whether supporting his programs might lock 50% of voters against them. It is important to recall that constitutionally, a senator is supposed to serve the people of his state, not the president.
Because public support wanes over the course of a presidency (though it sometimes blooms with nostalgia later in his term), it is essential to start a term with as much support as possible. Therefore, if Trump wants to get controversial bills passed, he must build his popularity quickly. His staff, particularly the vice president, will be examining every Republican senator who is up for re-election in 2018 to determine how to help sway their states’ voters. Trump’s fear will be that he will alienate his core while failing to make inroads with his enemies.
The Other Roadblock
The final point to consider is, of course, the use of filibusters. This is a deep tradition in the Senate, and it has served as another check on power that the founders would have been proud of. Any senator may filibuster a bill, and if a whole party does it, the filibuster can only be stopped by getting 60 votes in favor or by letting the senators go on until they drop.