Former Vice President Joe Biden for months has touted his more moderate positions over the more radical platform of rival Sen. Bernie Sanders, I-Vt. — but he's taken a noticeable left turn on a number of issues as he courts Sanders' progressive base and tries to lock down the nomination.

Biden has even gone so far as to state he was adopting parts of plans offered by Sanders himself, as well as former presidential candidate Sen. Elizabeth Warren, D-Mass.

Here's a look at the front-running Democratic primary candidate's evolving platform:

MARY ANNE MARSH: IN BIDEN-SANDERS DEBATE, SOLUTIONS WIN AND REVOLUTION LOSES

Free College

A key feature of Sanders’ platform has been his desire to offer free college for everyone. Biden now says he’s a fan, but placed a limit on his proposal that Sanders opposes.

“Bernie has put forward a plan that would make public colleges and universities free for families whose income is below $125,000. It's a good idea, and after consideration, I am proud to add it to my platform,” Biden tweeted Sunday.

Sanders’ campaign noted in response that the democratic socialist’s plan does not have any income-based restrictions and calls for tuition-free college for all.

“It's great that Joe Biden is now supporting a position that was in the Democratic platform four years ago," Sanders' team said in a statement. "Now, we have to go much further. We need to make all public universities, colleges and trade schools tuition-free for everyone like our high schools are."

Bankruptcy

In the same Twitter thread, Biden announced that he is also supporting Warren’s bankruptcy plan, which aims to simplify the bankruptcy process.

“Few people in the country understand how bankruptcy hurts working families more than Elizabeth Warren," Biden said. "Today, I am fully endorsing and adopting her bankruptcy plan, which she called 'Fixing Our Bankruptcy System to Give People a Second Chance.'"

Warren, in a Medium post earlier this year, said her plan would "make it easier for people being crushed by debt to obtain relief through bankruptcy," "expand people’s rights to take care of themselves and their children while they are in the bankruptcy process," end the "absurd rules that make it nearly impossible to discharge student loan debt in bankruptcy," and "let more people protect their homes and cars in bankruptcy so they can start from a firm foundation when they start to pick up the pieces and rebuild their financial lives."

Fracking

During Sunday's debate, after Sanders discussed putting an end to all fracking, Biden responded by saying, "No new fracking."

It was unclear at first if this was a call for a total ban on the practice going forward, but Biden's campaign later said that it was a reiteration of his previously stated position against new oil and gas drilling on federal lands.

CLICK HERE FOR THE FOX NEWS APP

Immigration

Biden has taken a more liberal stance on illegal immigration in recent weeks, saying that if he becomes president he will impose a 100-day freeze on deportation. He also said that people who enter the U.S. illegally will not be deported unless they commit a felony on American soil, even if they have a criminal record in another country.

This goes further than the policy advertised on Biden’s campaign website, which simply calls for ending “prolonged detention” as people await court hearings.

Fox News’ Gregg Re, Talia Kaplan and The Associated Press contributed to this report.