More gaffes from Donald Trump have depressed his popularity and made his path to 1,237 delegates more difficult than it appeared just a week ago. His limited policy knowledge and tendency to “wing it” during interviews has made even his staunchest advocates scratch their heads. Advocating punishment for women who have had abortions and belittling the wife of Senator Ted Cruz has caused his numbers with women to fall to alarming levels.

The result has been a further deterioration of his public standing. According to the latest surveys as compiled by the Huffington Post, Trump has a 31-63 percent unfavorable ratio and now trails Hillary Clinton, a weak candidate herself, by double digit margins.  

If Trump is to be defeated, it will be at the first contested Republican convention in 40 years in voting that goes beyond the first ballot for the first time since 1948. Here is how his nomination can be sidetracked:

He loses upcoming primaries. Trump is now an underdog in Wisconsin. Large upcoming states where he could be vulnerable include Indiana, Pennsylvania, California and New Jersey. Ted Cruz is not the ideal alternative candidate in these states, and John Kasich lacks the money and infrastructure. But Trump’s increasing unpopularity could result in split decisions where he wins fewer delegates and slows his momentum heading into Cleveland. Late losses will also make it harder to attract uncommitted delegates to give him a convention majority.

Anti-Trump activists win delegate slots at state and local conventions. Many states elect delegates separate and apart from the presidential candidate that wins the primary contest.   Delegates so elected are bound to the primary winner for one or more ballots, but are not bound to vote in any particular way on procedural issues at the convention.

In the past, the convention delegates have included larger shares of ideological conservative and libertarian activists who have had the time and patience to run for these positions. This has always been part of the system and is not some trick devised by elites to deny Trump the nomination. As a result, Trump could have considerably less support on convention organizational matters than he will during the presidential balloting.

He loses procedural fights at the convention. Trump will be vulnerable to preliminary votes on rules, credentials and platform. Anti-Trump forces will force votes to highlight these weaknesses and to destroy the argument that his nomination is “inevitable.” Delegates want to support a winner. If they feel that the momentum of the convention is heading elsewhere, that’s where they’ll head. That’s how conventions were stampeded in olden Times when “dark horses” were nominated. 

In 1952, for instance, Dwight Eisenhower won a series of credentials’ challenges and ultimately prevailed over pre- convention front runner and establishment favorite Senator Robert Taft.

In 1976, the convention turned on a rules fight forced by Ronald Reagan that would have required all candidates nominated for president to name their vice president prior to the presidential vote. The Reagan forces felt they might sway uncommitted delegates and others otherwise committed to vote for President Ford. Ford won the vote, barely, and won re-nomination the next night. Had Reagan prevailed, he might have been nominated in 1976 rather than four years later.

This year the Trump forces would be especially vulnerable in a platform fight. Their candidate holds far different views from most Republicans on issues such as his admiration for Vladimir Putin, U.S. engagement in the Middle East, private eminent domain, universal health care and the federal role in education. Trump might very well be goaded into a platform fight which he would lose and which might prove fatal to his candidacy.

Republicans warm to Cruz. Ted Cruz will have the second largest number of delegates. Adding the conservative activists who might be pledged to other candidates, he would be the logical alternative if Trump were to falter. 

John Kasich has strong general election credentials but has won only one primary.

It would be hard to see the Cleveland delegates turning to a consensus figure like Mitt Romney or Paul Ryan.

The most likely alternative to Trump is Cruz. Many question Cruz’s commitment to the GOP and have concerns about some of the shadowy figures in his campaign, but he runs stronger against Hillary Clinton and would be far less risky to down ballot Republicans.

Trump is still the favorite to win the nomination, but his path is narrowing. Who would have thought that a political convention in the Year of Our Lord 2016 would become "Must See TV"?  

A longtime Republican political activist, Frank Donatelli is executive vice president and director of federal public affairs for McGuireWoods Consulting LLC, and serves as counsel with McGuireWoods LLP.  During the 2008 presidential campaign, Sen. John McCain tapped Frank to serve as deputy chairman of the Republican National Committee, where he coordinated the RNC’s fundraising and organizing activities directly with the McCain-Palin presidential campaign. Frank is the former chairman of GOPAC, an organization dedicated to educating and electing a new generation of Republican leaders. He previously served as Political Director for President Ronald Reagan.